Your category names are wrong. Rule for figuring out the classname of a JGroups protocol from the name of it's config element in a protocol stack configuration is: org.jgroups.protocols. + element-name (Note there's no "jboss" in the package -- JGroups long predates it's association with JBoss.) For example: org.jgroups.protocols.TCPPING org.jgroups.protocols.pbcast.GMS View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4229741#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...