This looks to be the key to the problem: [org.jgroups.protocol.PING] down_handler thread for PING was interrupted (in order to be terminated), but is is still alive Machine1-int was detected as non-responsive and excluded from its group (see http://wiki.jboss.org/wiki/Wiki.jsp?page=FDVersusFD_SOCK for details); when it realized this is tried to stop and restart its JGroups channel in order to rejoin the group. The above message indicates a problem in stopping the channel, which I believe left a "zombie" channel running causing problems. Suggest you try upgrading JGroups to the latest compatible release, JGroups 2.4.2. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4137462#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...