Yes, I ran python setup.py develop. I'm starting to think that it might be a path issue, because if I add a logging statement to the django.wsgi file and output the contents of sys.path, I can see that it contains paths such as /usr/lib/python2.5/site-packages/Django-1.1-py2.5.egg/. The paths should be referring to the /lib/python.2.5/site-packages/ directory inside the virtualenv, shouldn't they?