If you are using JBoss AS 4.0.5.GA myfaces is installed into the AS so isn't needed in WEB-INF/lib. How did you install JBoss? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4034148#4034148 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4034148