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.
What have you done to debug this? Is the servlet even being called? Add some logging to the servlet to see if it is, or use the debug console in the browser to observe the behavior of the requests and responses.