I'm developing against Django 1.5 beta, and always got an error when installing. After a bit of fiddling, I know that installing django-categories in a clean (--no-site-packages) virtualenv
a) together with Django 1.4.3 works fine (pip install Django django-categories)
b) after having installed Django 1.4.3 works fine (pip install Django && pip install django-categories)
c) together with Django 1.5b2 works fine (surprisingly!) (pip install https://www.djangoproject.com/download/1.5b2/tarball/ django-categories)
d) after having installed Django 1.5b2 fails (pip install https://www.djangoproject.com/download/1.5b2/tarball/ && pip install django-categories)
The log is here: https://gist.github.com/560478e396afa1a289b1
I presume the error has to do with trying to import django.db.models.Q without having settings setup.
My workaround for now, in setup.py: Don't 'import categories' and manually set the version instead of getting it from categories.get_version(). Using get_version() is a nice touch, but seeing that both Django and the app are being imported to just get the version number, it might be easier to violate DRY than ensuring importing Django innards works without having a Django settings.py.