This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
This is a generic error that shows on a JSP when something goes wrong. In order for us to help you fix this, you will need to find the SystemOut log for your Application server and post the error message and stack trace that will appear there.
It would also be helpful to see the JSP code that was running when the error occurred.