problem new projet under jboss 4 with ecipse


I have a strange problem. I created a project HelloWorld with the last plugin of ecipse.

if I run this project under jboss 4.2, when i type http://localhost:8080/HelloWorld/, i get a exception on console

16:02:42,062 ERROR [
] Une exception lors de l'envoi de requête a détruit un évènement cycle de vie (lifecycle event) pour l'instance de classe à l'écoute (listener) org.jboss.web.jsf.integration.config.JBossJSFConfigureListener
	at com.sun.faces.application.WebappLifecycleListener.syncSessionScopedBeans(

and a message dialog box on firefox

Failed to load the widgetset: /HelloWorld/VAADIN/widgetsets/com.vaadin.terminal.gwt.DefaultWidgetSet/com.vaadin.terminal.gwt.DefaultWidgetSet.nocache.js

the same project runs on tomcat has no problem. what should i do make it run on jboss?

thanks in advance