Are you sure you have the latest drools-libraries and you don't have any other versions hanging around the server? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4073825#4073825 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4073825