Struts 2 on Google app engine. problem

Question

Hi. I use struts2 in google app engine
I had an error with my application.

result 'null' not found

But when I created listener Ognl this error is not displaying.

http://whyjava.wordpress.com/2009/08/30/creating-struts2-application-on-google-app-engine-gae/

to resolve this problem I created an ServletContextListner which will set OGNL security manager to null when the context is initialized. when I created this listener this error is not displaying.

But now I have blank page without any text in my browser. When I call to any page, nothing display. Why? Please, help me.