Always look at the "cause by" to determine the root cause: Caused by: java.lang.ClassCastException: org.jboss.portal.portlet.samples.SimplestHelloWorldPortlet cannot be cast to javax.portlet.Portlet Two possibilities: 1) Your portlet does not extend javax.portlet.GenericPortlet (which extends javax.portlet.Portlet). 2) You included the portlet API JAR file in your portlet's WAR file. If so, remove it. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4202187#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...