diff --git a/src/pisi/install.py b/src/pisi/install.py
index 589a3390..5eae44c9 100644
--- a/src/pisi/install.py
+++ b/src/pisi/install.py
@@ -27,7 +27,8 @@ def install_package_file(package_fn):
     metadata = MetaData()
     metadata.read(install_dir() + '/metadata.xml')
     # check package semantics
-    metadata.verify()
+    if not metadata.verify():
+        raise InstallError("MetaData format wrong")
 
     # check file system requirements
     # what to do if / is split into /usr, /var, etc.?
diff --git a/src/pisi/xmlfile.py b/src/pisi/xmlfile.py
index 6b100073..5dbef393 100644
--- a/src/pisi/xmlfile.py
+++ b/src/pisi/xmlfile.py
@@ -99,7 +99,7 @@ class XmlFile(object):
 
     def verifyRootTag(self):
         if self.dom.documentElement.tagName != self.rootTag:
-            raise XmlError("Root tagname not " % self.rootTag % " as expected")
+            raise XmlError("Root tagname not " + self.rootTag + " as expected")
 
     def getNode(self, tagPath):
 	"""returns the *first* matching node for given tag path."""