Perhaps a silly question, but I have just downloaded the evaluation license and would like to know what I can't do with the evaluation license that I will be able to do with a full license.

I can't figure out how to add bugs, so I'm guessing this is one of the functions that is not available with the evaluation license?

Evaluation version is fully-functional. You probably did not specify your username and password when creating connection to Bugzilla -- you can do it by opening File -- Connection Manager and editing settings.

Hope this helps!
-- Igor