How can I fix the Error: Unable to convert auth_user 65 to forum_user?

C:\Python27\Lib\site-packages\fantasy_island\forum\middleware\extended_user.py TIME: 2011-11-01 10:58:24,444 MSG: extended_user.py:process_request:23 Unable to convert auth_user 65 to forum_user: 
Traceback (most recent call last):
File "C:\Python27\Lib\site-packages\fantasy_island\forum\middleware\extended_user.py", line 12, in process_request
request.user = request.user.user
File "C:\Python27\Lib\site-packages\django\db\models\fields\related.py", line 239, in __get__
rel_obj = self.related.model._base_manager.using(db).get(**params)
File "C:\Python27\Lib\site-packages\django\db\models\manager.py", line 189, in using
return self.get_query_set().using(*args, **kwargs)
File "C:\Python27\Lib\site-packages\fantasy_island\forum\models\base.py", line 69, in get_query_set
return CachedQuerySet(self.model)
TypeError: 'NoneType' object is not callable

I get this error when I tried to login to the system. I use django-sso and it was working well before. I didn't understand what happened then. I started to get this error and I can't reach any of the questions now. What can I do? I can't get any data from db because of this error