How are you installing Mailman? Where are you getting zope.interface from? If you're using a virtualenv, you should use --no-site-packages to ensure you're not getting pollution from older version of the required packages (i.e. virtualenv will install everything from pypi).
How are you installing Mailman? Where are you getting zope.interface from? If you're using a virtualenv, you should use --no-site-packages to ensure you're not getting pollution from older version of the required packages (i.e. virtualenv will install everything from pypi).