diff --git a/pisi/actionsapi/pisitools.py b/pisi/actionsapi/pisitools.py
index 06161715..56789a85 100644
--- a/pisi/actionsapi/pisitools.py
+++ b/pisi/actionsapi/pisitools.py
@@ -174,7 +174,7 @@ def dosed(sourceFiles, findPattern, replacePattern = ''):
 
     for sourceFile in glob.glob(sourceFiles):
         if can_access_file(sourceFile):
-            for line in fileinput.input(sourceFile, inplace = 1):
+            for line in fileinput.input(str(sourceFile), inplace = 1):
                 #FIXME: In-place filtering is disabled when standard input is read
                 line = re.sub(findPattern, replacePattern, line)
                 sys.stdout.write(line)