You've got a lot of models in that file. Which one are you trying to
save when it throws the error?
By the way, I notice that your "ItemWithMedia" class is probably
creating a database table.. if you never need to manipulate it direct
(ie, you only make subclasses of it), I might suggest putting this in
# ... all of your old stuff goes here
abstract = True
That way Django knows it's just a base class.
Not sure what the problem is, yet...