Getting the following kinds of warnings when running most python scripts in the command line:
/Library/Python/2.6/site-packages/virtualenvwrapper/hook_loader
I had this sort of Python packaging hell visit today too.
Running Python 2.7.3 on Ubuntu, using namespace packages and using zc.buildout.
Finally, updating system wide Distribute from older version 0.6.30 to latest version 0.6.35 resolved the problem.