It looks like you are requiring an abstract class and when the session starts, something is trying to create an instance of the abstract class. It isn't possible to create an instance of an abstract class directly, so you get the error. If you want to use an abstract class, create a child class of the abstract class and create an instance of the child class.
Last edited by qjensen; 12-17-2010 at 09:38 AM.
Reason: first explanation was way too involved :)