diff --git a/pisi/__init__.py b/pisi/__init__.py
index a8825a19..e0899e6c 100644
--- a/pisi/__init__.py
+++ b/pisi/__init__.py
@@ -8,6 +8,16 @@
 # Please read the COPYING file.
 #
 
-# PISI package version
-__version__ = "0.1"
+# PISI version
 
+__version__ = "0.2"
+
+__all__ = [ 'toplevel', 'packagedb', 'installdb' ]
+
+class PisiError(Exception):
+    """Class of exceptions that lead to program termination"""
+    pass
+
+class PisiException(Exception):
+    """Class of exceptions that must be caught and handled within PISI"""
+    pass
diff --git a/pisi/actionsapi/__init__.py b/pisi/actionsapi/__init__.py
index 219aa50c..7698c446 100644
--- a/pisi/actionsapi/__init__.py
+++ b/pisi/actionsapi/__init__.py
@@ -10,3 +10,11 @@
 
 # pisi.actionsapi version
 __version__ = '0.1'
+
+import pisi
+
+class ActionsApiError(pisi.PisiError):
+    pass
+
+class ActionsApiException(pisi.PisiException):
+    pass
diff --git a/pisi/actionsapi/autotools.py b/pisi/actionsapi/autotools.py
index 2a47ef3b..d30d4ed6 100644
--- a/pisi/actionsapi/autotools.py
+++ b/pisi/actionsapi/autotools.py
@@ -18,10 +18,11 @@ import os
 from pisi.ui import ui
 
 # ActionsAPI Modules
-import get
-from shelltools import system
-from shelltools import can_access_file
-from libtools import gnuconfig_update
+import pisi.actionsapi
+import pisi.actionsapi.get as get
+from pisi.actionsapi.shelltools import system
+from pisi.actionsapi.shelltools import can_access_file
+from pisi.actionsapi.libtools import gnuconfig_update
 
 class ConfigureError(Exception):
     def __init__(self, Exception):
diff --git a/pisi/actionsapi/coreutils.py b/pisi/actionsapi/coreutils.py
index 30a6357e..c8f5c8b4 100644
--- a/pisi/actionsapi/coreutils.py
+++ b/pisi/actionsapi/coreutils.py
@@ -16,6 +16,8 @@ import sys
 import re
 from itertools import izip, imap, count, ifilter, ifilterfalse
 
+import pisi.actionsapi as actionsapi
+
 def cat(filename):
     return file(filename).xreadlines()
 
diff --git a/pisi/actionsapi/libtools.py b/pisi/actionsapi/libtools.py
index cd4a75d6..621297aa 100644
--- a/pisi/actionsapi/libtools.py
+++ b/pisi/actionsapi/libtools.py
@@ -19,8 +19,9 @@ import shutil
 from pisi.ui import ui
 
 # ActionsAPI Modules
-from shelltools import chmod, makedirs
-import get
+import pisi.actionsapi
+from pisi.actionsapi.shelltools import chmod, makedirs
+import pisi.actionsapi.get
 
 def preplib(sourceDirectory):
     os.system('/sbin/ldconfig -n -N %s' % get.installDIR() + sourceDirectory)
diff --git a/pisi/actionsapi/pisitools.py b/pisi/actionsapi/pisitools.py
index b7abd843..8c1c2f34 100644
--- a/pisi/actionsapi/pisitools.py
+++ b/pisi/actionsapi/pisitools.py
@@ -20,9 +20,10 @@ import fileinput
 import re
 
 # ActionsAPI Modules
-import get
-from pisitools_functions import *
-from shelltools import *
+import pisi.actionsapi
+import pisi.actionsapi.get as get
+from pisi.actionsapi.pisitools_functions import *
+from pisi.actionsapi.shelltools import *
 
 def dobin(sourceFile, destinationDirectory = '/usr/bin'):
     '''insert a executable file into /bin or /usr/bin'''
diff --git a/pisi/actionsapi/pisitools_functions.py b/pisi/actionsapi/pisitools_functions.py
index b47cf0ef..6509b97b 100644
--- a/pisi/actionsapi/pisitools_functions.py
+++ b/pisi/actionsapi/pisitools_functions.py
@@ -18,7 +18,8 @@ import os
 import glob
 
 # ActionsAPI Modules
-from shelltools import *
+import pisi.actionsapi
+from pisi.actionsapi.shelltools import *
 
 class FileError(Exception):
     pass
diff --git a/pisi/actionsapi/shelltools.py b/pisi/actionsapi/shelltools.py
index 5e275f50..1282c1ed 100644
--- a/pisi/actionsapi/shelltools.py
+++ b/pisi/actionsapi/shelltools.py
@@ -20,7 +20,8 @@ import shutil
 from pisi.ui import ui
 
 # ActionsAPI Modules
-import get
+import pisi.actionsapi
+import pisi.actionsapi.get
 
 def can_access_file(sourceFile):
     '''test the existence of file'''
diff --git a/pisi/actionsapi/variables.py b/pisi/actionsapi/variables.py
index 91196a83..0486da17 100644
--- a/pisi/actionsapi/variables.py
+++ b/pisi/actionsapi/variables.py
@@ -15,8 +15,8 @@
 from os import getenv, environ
 
 # Pisi-Core Modules
-import pisi.config
-import pisi.constants
+import pisi.config                      # That was the only correct
+import pisi.constants                   # use before changing to abs. imports
 
 # Set individual information, that are generally needed for ActionsAPI
 
diff --git a/pisi/archive.py b/pisi/archive.py
index b6c0905a..b46b869c 100644
--- a/pisi/archive.py
+++ b/pisi/archive.py
@@ -9,21 +9,23 @@
 #
 # Please read the COPYING file.
 #
-
 # Archive module provides access to regular archive file types.
 # maintainer baris and meren
 
-#standard lisbrary modules
+# standard library modules
 import os
 import tarfile
 import zipfile
 
-#pisi modules
-import util
+# PiSi modules
+import pisi
+import pisi.util as util
 
-class ArchiveError(Exception):
+
+class ArchiveError(pisi.PisiError):
     pass
 
+
 class ArchiveBase(object):
     """Base class for Archive classes."""
     def __init__(self, filepath, atype):
@@ -38,6 +40,7 @@ class ArchiveBase(object):
 
         os.makedirs(self.targetDir)
 
+
 class ArchiveTar(ArchiveBase):
     """ArchiveTar handles tar archives depending on the compression
     type. Provides access to tar, tar.gz and tar.bz2 files. 
@@ -68,6 +71,7 @@ class ArchiveTar(ArchiveBase):
         os.chdir(oldwd)
         tar.close()
 
+
 class ArchiveZip(ArchiveBase):
     """ArchiveZip handles zip archives. 
 
@@ -180,6 +184,7 @@ class ArchiveZip(ArchiveBase):
         self.close()
         return 
 
+
 class Archive:
     """Archive is the main factory for ArchiveClasses, regarding the
     Abstract Factory Pattern :)."""
diff --git a/pisi/build.py b/pisi/build.py
index 8fa0a86b..beeec95d 100644
--- a/pisi/build.py
+++ b/pisi/build.py
@@ -17,17 +17,19 @@
 import os
 import sys
 
-import util
-from ui import ui
-from constants import const
-from config import config
-from context import BuildContext
-from sourcearchive import SourceArchive
-from files import Files, FileInfo
-from metadata import MetaData
-from package import Package
+import pisi
+import pisi.util as util
+from pisi.ui import ui
+from pisi.constants import const
+from pisi.config import config
+from pisi.context import BuildContext
+from pisi.sourcearchive import SourceArchive
+from pisi.files import Files, FileInfo
+from pisi.metadata import MetaData
+from pisi.package import Package
 
-class PisiBuildError(Exception):
+
+class PisiBuildError(pisi.PisiError):
     pass
 
 
diff --git a/pisi/cli/commands.py b/pisi/cli/commands.py
index e6aedf9c..3a4fccfe 100644
--- a/pisi/cli/commands.py
+++ b/pisi/cli/commands.py
@@ -12,9 +12,10 @@
 
 import sys
 from optparse import OptionParser
+
 import pisi
 from pisi.purl import PUrl
-from common import *
+from pisi.cli.common import *
 import pisi.toplevel
 from pisi.ui import ui
 
@@ -27,6 +28,7 @@ def commandsString():
         s += x + '\n'
     return s
 
+
 # helper functions
 def cmdObject(cmd, fail=False):
 
@@ -40,6 +42,7 @@ def cmdObject(cmd, fail=False):
     else:
         return None
 
+
 class Command(object):
     """generic help string for any command"""
 
@@ -99,6 +102,7 @@ class Command(object):
         print 'Program terminated abnormally.'
         sys.exit(-1)
 
+
 class Help(Command):
     """Prints usage
 
@@ -122,6 +126,7 @@ for that command.
             obj = cmdObject(arg, True)
             obj.help()
 #            print "\n",self.parser.format_option_help()
+
                 
 class Build(Command):
     """Build a PISI package using a pspec.xml file
@@ -143,6 +148,7 @@ fetch all necessary files and build the package for you.
         for arg in self.args:
             pisi.toplevel.build(arg, self.authInfo)
 
+
 class PackageOp(Command):
     """Abstract package operation command"""
     def __init__(self):
@@ -173,6 +179,7 @@ class PackageOp(Command):
             #    pisi.comariface.finalize()
             #except pisi.comariface.ComarError:
             #    ui.error('Comar error encountered\n')
+
         
 class Install(PackageOp):
     """Install PISI packages
@@ -195,6 +202,7 @@ specified a package name, it should exist in a specified repository.
         pisi.toplevel.install(self.args)
         self.finalize()
 
+
 class Upgrade(PackageOp):
     """Upgrade PISI packages
 
@@ -216,6 +224,7 @@ specified a package name, it should exist in a specified repository.
         pisi.toplevel.upgrade(self.args)
         self.finalize()
 
+
 class Remove(PackageOp):
     """Remove PISI packages
 
@@ -236,6 +245,7 @@ Remove a package from your system. Just give the package name to remove.
         pisi.toplevel.remove(self.args)
         self.finalize()
 
+
 class ConfigurePending(PackageOp):
     """configure pending packages"""
     
@@ -251,6 +261,7 @@ class ConfigurePending(PackageOp):
         pisi.toplevel.configure_pending()
         self.finalize()
 
+
 class Info(Command):
     """Display information about a package 
 
@@ -277,6 +288,7 @@ TODO: Some description...
             metadata, files = pisi.toplevel.info(arg)
             print metadata.package
 
+
 class Index(Command):
     """Index PISI files in a given directory
 
@@ -302,6 +314,7 @@ TODO: Some description...
             print 'Indexing only a single directory supported'
             return
 
+
 class ListInstalled(Command):
     """Print the list of all installed packages  
 
@@ -328,6 +341,7 @@ TODO: Some description...
             else:
                 print package
 
+
 class UpdateRepo(Command):
     """Update the databases of a repository
 
@@ -348,6 +362,7 @@ TODO: Some description...
         for repo in self.args:
             pisi.toplevel.update_repo(repo)
 
+
 class AddRepo(Command):
     """Add a repository
 
@@ -369,6 +384,7 @@ TODO: Some description...
             self.help()
             return
 
+
 class RemoveRepo(Command):
     """Remove a repository
 
@@ -389,6 +405,7 @@ TODO: Some description...
             self.help()
             return
 
+
 class ListRepo(Command):
     """List repositories
 
@@ -500,6 +517,7 @@ for you.
         for arg in self.args:
             pisi.toplevel.build_until(arg, state, self.authInfo)
 
+
 class BuildUnpack(Command):
     """Unpack the source archive
 
@@ -559,6 +577,7 @@ TODO: desc.
         for arg in self.args:
             pisi.toplevel.build_until(arg, "buildaction", self.authInfo)
 
+
 class BuildInstall(Command):
     """Install to the sandbox
 
@@ -578,6 +597,7 @@ TODO: desc.
         for arg in self.args:
             pisi.toplevel.build_until(arg, "installaction", self.authInfo)
 
+
 class BuildPackage(Command):
     """Setup the source
 
@@ -597,6 +617,8 @@ TODO: desc.
         for arg in self.args:
             pisi.toplevel.build_until(arg, "buildpackages", self.authInfo)
 
+# command dictionary
+
 commands = {"help": Help,
             "build": Build,
             "build-until": BuildUntil,
diff --git a/pisi/cli/pisicli.py b/pisi/cli/pisicli.py
index 91cf7e63..20d4b373 100644
--- a/pisi/cli/pisicli.py
+++ b/pisi/cli/pisicli.py
@@ -16,8 +16,8 @@ from optparse import OptionParser
 import pisi
 import pisi.operations
 from pisi.purl import PUrl
-from common import *
-from commands import *
+from pisi.cli.common import *
+from pisi.cli.commands import *
 
 class ParserError(Exception):
     pass
diff --git a/pisi/comariface.py b/pisi/comariface.py
index 6c34811f..c57006a3 100644
--- a/pisi/comariface.py
+++ b/pisi/comariface.py
@@ -13,7 +13,9 @@
 import socket
 import struct
 
-class ComarError(Exception):
+import pisi
+
+class ComarError(pisi.PisiError):
 	pass
 
 class ComarIface:
diff --git a/pisi/config.py b/pisi/config.py
index 1e9b1d85..084b874c 100644
--- a/pisi/config.py
+++ b/pisi/config.py
@@ -16,8 +16,9 @@
 # Authors: Baris Metin <baris@uludag.org.tr
 #          Eray Ozkural <eray@uludag.org.tr>
 
-from constants import const
-from configfile import ConfigurationFile
+import pisi
+from pisi.constants import const
+from pisi.configfile import ConfigurationFile
 
 class Config(object):
     """Config Singleton"""
@@ -27,9 +28,6 @@ class Config(object):
         self.values = ConfigurationFile("/etc/pisi/pisi.conf")
         self.destdir = self.values.general.destinationdirectory
 
-    def __call__(self):
-        return self
-
     # directory accessor functions
     # here is how it goes
     # x_dir: system wide directory for storing info type x
diff --git a/pisi/constants.py b/pisi/constants.py
index 58427016..c725066a 100644
--- a/pisi/constants.py
+++ b/pisi/constants.py
@@ -16,6 +16,8 @@
 
 # Author: Baris Metin <baris@uludag.org.tr
 
+import pisi
+
 class _constant:
     "Constant members implementation"
     class ConstError(TypeError):
diff --git a/pisi/fetcher.py b/pisi/fetcher.py
index 18efdd38..8a3c421e 100644
--- a/pisi/fetcher.py
+++ b/pisi/fetcher.py
@@ -21,13 +21,16 @@ import os
 from base64 import encodestring
 
 # pisi modules
-import util
-from purl import PUrl
-from ui import ui
+import pisi
+import pisi.util as util
+from pisi.purl import PUrl
+from pisi.ui import ui
 
-class FetchError (Exception):
+
+class FetchError(pisi.PisiError):
     pass
 
+
 # helper functions
 def fetchUrl(url, dest, progress=None):
     fetch = Fetcher(url, dest)
diff --git a/pisi/graph.py b/pisi/graph.py
index c419f90c..7217596a 100644
--- a/pisi/graph.py
+++ b/pisi/graph.py
@@ -16,7 +16,9 @@ ver = sys.version_info
 if ver[0] <= 2 and ver[1] < 4:
     from sets import Set as set
 
-class CycleError(Exception):
+# not a PISI error!
+
+class CycleException(Exception):
     pass
 
 class digraph(object):
diff --git a/pisi/install.py b/pisi/install.py
index de13d466..436b822e 100644
--- a/pisi/install.py
+++ b/pisi/install.py
@@ -16,21 +16,22 @@
 
 import os
 
-from specfile import *
-from package import Package
-from config import config
-from constants import const
-from ui import ui
-from installdb import installdb
-import packagedb
-from packagedb import inst_packagedb
-import dependency
-from metadata import MetaData
-from comariface import comard
-import operations
+import pisi
+from pisi.specfile import *
+from pisi.package import Package
+from pisi.config import config
+from pisi.constants import const
+from pisi.ui import ui
+from pisi.installdb import installdb
+import pisi.packagedb as packagedb
+from pisi.packagedb import inst_packagedb
+import pisi.dependency as dependency
+from pisi.metadata import MetaData
+from pisi.comariface import comard
+import pisi.operations as operations
 #import conflicts
 
-class InstallError(Exception):
+class InstallError(pisi.PisiError):
     pass
 
 class Installer:
diff --git a/pisi/installdb.py b/pisi/installdb.py
index 5cef9af2..6bb25e66 100644
--- a/pisi/installdb.py
+++ b/pisi/installdb.py
@@ -19,14 +19,17 @@ import os
 import fcntl
 
 # PiSi
-import lockeddbshelve as shelve
-from constants import const
-from files import Files
-import util
+import pisi
+import pisi.lockeddbshelve as shelve
+from pisi.constants import const
+from pisi.files import Files
+import pisi.util as util
 
-class InstallDBError(Exception):
+
+class InstallDBError(pisi.PisiError):
     pass
 
+
 class InstallDB:
 
     def __init__(self):
diff --git a/pisi/operations.py b/pisi/operations.py
index e9603b57..fc446689 100644
--- a/pisi/operations.py
+++ b/pisi/operations.py
@@ -12,11 +12,13 @@
 
 import os
 
-from config import config
-from constants import const
-from ui import ui
-from purl import PUrl
-import util, packagedb
+import pisi
+from pisi.config import config
+from pisi.constants import const
+from pisi.ui import ui
+from pisi.purl import PUrl
+import pisi.util as util
+import pisi.packagedb as packagedb
 
 # single package operations
 
diff --git a/pisi/package.py b/pisi/package.py
index 1b64dd73..2be88629 100644
--- a/pisi/package.py
+++ b/pisi/package.py
@@ -17,16 +17,19 @@
 
 from os.path import join
 
-import archive
-from constants import const
-from config import config
-from purl import PUrl
-from metadata import MetaData
-from files import Files
+import pisi
+import pisi.archive as archive
+from pisi.constants import const
+from pisi.config import config
+from pisi.purl import PUrl
+from pisi.metadata import MetaData
+from pisi.files import Files
 
-class PackageError(Exception):
+
+class PackageError(pisi.PisiError):
     pass
 
+
 class Package:
     """PISI Package Class provides access to a pisi package (.pisi
     file)."""
diff --git a/pisi/packagedb.py b/pisi/packagedb.py
index 17795414..5dedb105 100644
--- a/pisi/packagedb.py
+++ b/pisi/packagedb.py
@@ -22,12 +22,13 @@
 #from bsddb.dbshelve import DBShelf
 import bsddb.dbshelve as shelve
 import os, fcntl
-
-import util
-from config import config
 from bsddb import db
 
-class PackageDBError(Exception):
+import pisi
+import pisi.util as util
+from pisi.config import config
+
+class PackageDBError(pisi.PisiError):
     pass
 
 class PackageDB(object):
diff --git a/pisi/sourcearchive.py b/pisi/sourcearchive.py
index 64a482d6..59d94aae 100644
--- a/pisi/sourcearchive.py
+++ b/pisi/sourcearchive.py
@@ -20,15 +20,15 @@ from os import access, R_OK
 
 
 # pisi modules
-from archive import Archive
-from purl import PUrl
-from ui import ui
-from config import config
-from fetcher import fetchUrl
-import util
+import pisi
+from pisi.archive import Archive
+from pisi.purl import PUrl
+from pisi.ui import ui
+from pisi.config import config
+from pisi.fetcher import fetchUrl
+import pisi.util as util
 
-
-class SourceArchiveError(Exception):
+class SourceArchiveError(pisi.PisiError):
     pass
 
 class SourceArchive:
diff --git a/pisi/util.py b/pisi/util.py
index 51a924a7..58f7943d 100644
--- a/pisi/util.py
+++ b/pisi/util.py
@@ -24,14 +24,15 @@ import shutil
 import statvfs
 
 # pisi modules
-from ui import ui
-from constants import const
-from config import config
+import pisi
+from pisi.ui import ui
+from pisi.constants import const
+from pisi.config import config
 
-class FileError(Exception):
+class FileError(pisi.PisiError):
     pass
 
-class UtilError(Exception):
+class UtilError(pisi.PisiError):
     pass
 
 
diff --git a/pisi/xmlext.py b/pisi/xmlext.py
index af92274b..50b0d34f 100644
--- a/pisi/xmlext.py
+++ b/pisi/xmlext.py
@@ -16,8 +16,9 @@
 # Authors:  Eray Ozkural <eray@uludag.org.tr>
 #           Baris Metin <baris@uludag.org.tr
 
+import pisi
 
-class XmlError(Exception):
+class XmlError(pisi.PisiError):
     pass
 
 def getNodeAttribute(node, attrname):