I have additional information (for my particular case): Our web application uses the Richfaces tree widget http://labs.jboss.com/file-access/default/members/jbossrichfaces/freezone... In implementing the necessary data structure support, I encountered a class loading problem, and a posted solution: http://jboss.com/index.html?module=bb&op=viewtopic&t=107687 The solution involves setting | <attribute name="UseJBossWebLoader">true</attribute> | in server\default\deploy\jboss-web.deployer\META-INF\jboss-service.xml and indeed, this does solve the Tree/TreeNode class not found error. Unfortunately, it also breaks SEAM email. Further investigation pending... View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4050176#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...