This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Looks like you have not posted your complete query .
The post would definitely need to include more information on what you were trying to do, code pieces etc. and when you are facing this exception if you want others to look at the issue and provide any inputs.