rspec problems mocking classes based on mongoid

I am getting errors when running my rspecs.
My project uses rails 3, mongoid, factory_girl, rspec 2.0.0.beta.22,
rspec-mocs, etc

http://pastebin.com/raw.php?i=WkaGiFag

Getting: Failure/Error: @product = assign(:product,
stub_model(Product, undefined method `to_sym' for nil:NilClass

I'm pretty sure stub_model has no clue on how to handle objects based
on mongoid.

Any ideas?