Thanks for the stack trace; yeah that's the JBAS-7123 condition. It's already fixed in SVN and will be fixed in the 5.2 which should be out late this year. It will also be fixed in JBoss Enterprise Application Platform 5. As to a workaround for AS 5.1.0, the only one I can see is to add this to your startup command: -Dorg.apache.catalina.STRICT_SERVLET_COMPLIANCE=false That will prevent the org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:132) call that is leading to the problem. That has a number of effects on the behavior of JBoss Web though, many of which I don't claim to understand. This doc gives a good overview of the effect of that flag: http://tomcat.apache.org/tomcat-6.0-doc/config/systemprops.html The "every request that is associated with a session will cause the session's last accessed time to be updated regardless of whether or not the request explicity accesses the session. (SRV.7.6) " bit on that page is the one specifically relevant to this issue. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4257100#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...