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.
Bear is right. You probably got an SQLException, but because you ignore it you don't know.
There are two easy fixes:
1) 2) Both will cause the exception to show up on the page (with the first one having a 500 HTML error code (internal server error)). Use this information to find the cause of the error.