If you are using
Tomcat7 and
DWR.3.0-RC1-116.jar file then you will get CSRF Security Error:
java.lang.SecurityException: CSRF Security Error
Solution:
One fix is to make the default Tomcat 7 tomcat/conf/context.xml (or your application's context XML) put the useHTTPOnly on the Context element, like so: <Context useHttpOnly="false">
You can also fix this issue by using the latest DWR build
refer the following for more details
http://mohansrihari.wordpress.com/2012/08/16/integrating-dwr3-and-spring3/