Comment 9 for bug 1085425

For anyone running into this problem, the reason probably is you've installed a Zope module from some other source than the official repository. I managed to fix this with the following commands:

cd /usr/local/lib/python2.7/dist-packages/zope
sudo ln -s /usr/share/pyshared/zope/interface/

Credit for the solution goes to: http://anibalpacheco.com/?p=51