Under Python 3.3, site.py can run into an import loop if distribute is on the sys.path more than once (or a second version of distribute is on the sys.path - don't blame me, sys.path can be messy.). This is likely due to changes to the import machinery .
To fix this, the
import imp statement has been moved further down, into the try/except clause, to catch cases when distribute tries to load itself or a sibling.
Patch 'site.py': [[https://bitbucket.org/stefanholek/distribute/changeset/dfc6aafc0d21]]
 Python 3.3 import changes: http://docs.python.org/dev/whatsnew/3.3.html#using-importlib-as-the-implementation-of-import