My app throws exceptions when certain request are not valid, pretty standard stuff. I setup an error page using isErrorPage="true" to display the details related to these exceptions. When I deploy my app on JRun 4, and the application throws its error, I receive an NPE (resulting in an http 500) right at the line where the jsp error page prints the implicit exception object's getMessage(). Deploying the same app on my local tomcat instance, it handles the exception object fine, no NPE. Is there some "extra" setting that needs to be set when you have a JRun app handle errors as such? Any tips on this will be greatly appreciated, thanks.