acts_as_authenticated current_user in a model with rails 2.02 fails

Hi - I'm using acts_as_authenticated on my local machine, in a model I ask

if current_user

and it works locally no problem. I upload to my host, and suddenly I get :

undefined local variable or method `current_user' for #<Class: 0x2b0e8c321ca0>

both local and host user rails 2.02. using ruby 1.86 locally, and 1.85 on the host, but that shouldn't matter.

Anyone have any ideas why?

Thanks, Dino