"max.andersen(a)jboss.com" wrote : you are referring to jboss 5 but the logs say you are uusing jboss-4.2..which one is it ? I installed both servers, but for the example I used JBoss 4.2. I later tested on JBoss 5, with the same error (displayed different, but same cause). "max.andersen(a)jboss.com" wrote : anyhow, JDK 6 is known to cause problems so use JDK 5 for the server. I removed all Server Runtimes and added the servers again, using JDK 5 now. The error continues. I will try supplying my own JSF implementation, since that seems to be the problem. Thank you. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4159008#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...