Django is returning RuntimeError instead of 404
try not loading all middleware modules, just comment them all in the settings and see if the problem is somewhere there.
In my Django project I am having RUntimeError when I'm supposed to get a 404. The description says:

Exception Value: maximum recursion depth exceeded

The error only occurs when I try to access a non-existent page (the correct result would be a 404 page isn't it?). Is this a Django bug or is it my fault? I will provide more information if needed.
EDIT: I have tried syncing the database (actually drop the database and sync it from scratch), restarting the server and even commenting out all the urlpatterns in all urls.py files.
EDIT: This is what the traceback looks like:

File "/usr/lib/pymodules/python2.6/django/core/handlers/base.py" in get_response
  83.                     request.path_info)
File "/usr/lib/pymodules/python2.6/django/core/urlresolvers.py" in resolve
  218.                     sub_match = pattern.resolve(new_path)
File "/usr/lib/pymodules/python2.6/django/core/urlresolvers.py" in resolve
  218.                     sub_match = pattern.resolve(new_path)
File "/usr/lib/pymodules/python2.6/django/core/urlresolvers.py" in resolve
  218.                     sub_match = pattern.resolve(new_path)

And the last few lines are:

File "/usr/lib/pymodules/python2.6/django/core/urlresolvers.py" in resolve
  218.                     sub_match = pattern.resolve(new_path)
File "/usr/lib/pymodules/python2.6/django/core/urlresolvers.py" in resolve
  216.             for pattern in self.url_patterns:
File "/usr/lib/pymodules/python2.6/django/core/urlresolvers.py" in _get_url_patterns
  245.         patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)