Thanks for your reply, unfortunately no luck. I have looked at the SeamDiscs example in CVS which uses Trinidad. It looks from it that the A4J filter is no longer required in web.xml. I have followed the SeamDiscs example very closely still to no avail. No matter what I try, I still get the above error when trying to access a page with Trinidad Components. Pages without Trinidad (the sample "home" page) load fine. I am sure it is something simple that I am overlooking. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4049807#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...