[Zope] error with repozo.py

Hello, I get an error when I want to create a backup with repozo.py. Traceback (most recent call last): File "./repozo.py", line 74, in ? from ZODB.FileStorage import FileStorage ImportError: No module named ZODB.FileStorage I already searched with google for a solution. I found that it could be a problem with PYTHONPATH, but I've set this path already. What else can be wrong ? Regards, Martin Koekenberg