This is an old bug fixed in 3.2 that never was ported to head and so never made it into 4.0.

2003-10-07 14:17:19,845 ERROR [JMSContainerInvoker]
(Thread Pool Worker-9921) Exception in JMSCI message listener
java.lang.NullPointerException
at java.util.Hashtable.put(Hashtable.java:386)
org.jboss.ejb.plugins.jms.DLQHandler.makeWritable(DLQHandler.java:288)
org.jboss.ejb.plugins.jms.DLQHandler.sendMessage(DLQHandler.java:239)
org.jboss.ejb.plugins.jms.DLQHandler.handleRedeliveredMessage(DLQHandler.java:213)
org.jboss.ejb.plugins.jms.JMSContainerInvoker$MessageListenerImpl.onMessage(JMSContainerInvoker.java:1039)
org.jboss.jms.asf.StdServerSession.onMessage(StdServerSession.java:256)
org.jboss.mq.SpyMessageConsumer.sessionConsumerProcessMessage(SpyMessageConsumer.java:633)
org.jboss.mq.SpyMessageConsumer.addMessage(SpyMessageConsumer.java:433)
org.jboss.mq.SpySession.run(SpySession.java:298)
org.jboss.jms.asf.StdServerSession.run(StdServerSession.java:180)
EDU.oswego.cs.dl.util.concurrent.PooledExecutor$Worker.run(PooledExecutor.java:732)
at java.lang.Thread.run(Thread.java:536)