Java EE (Java Enterprise Edition) General Discussion

We"re using two Message Driven Beans (say MDB1 and MDB2) and two EJBs (say EJB1 and EJB2) in a module in our project to implement JMS Embedded messaging on WAS5.1 (using WSAD5.1.2 environment)
The MDB2"s onMessage() listens to a queue written by EJB1 and MDB1"s onMessage() also listens to a queue written by EJB1.
Flow:-
EJB1 starts first and writes a queue to the MDB2, which asynchronously invokes the EJB2 and this EJB2, after calls to a few utility classes invokes EJB1. Then, EJB1, with the Vector input from EJB2 writes a queue to be captured by MDB1.
The first flow of EJB1 --> MDB2 works fine, but the second part (EJB1 --> MDB1) is failing and the MDB2 is also getting shut down because of this. The cause of this is a <b>javax.ejb.TransactionRolledbackLocalException: ; nested exception is: com.ibm.ws.exception.WsEJBException</b>
Can someone who"s already faced such a challege kindly help?

This is the stack trace:- (for sake of clarity, MSSPriceChangeAlertMDB in the below trace is the MDB2)
[8/9/05 19:55:11:951 EDT] 234d1b6e RegisteredRes E WTRN0063E: An illegal attempt to commit a one phase capable resource with existing two phase capable resources has occurred.
[8/9/05 19:55:14:467 EDT] 2a50db6e JMSExceptionL E WMSG0018E: Error on JMSConnection for MDB MSSPriceChangeAlertMDB , JMSDestination jms/MarketDataQueue : javax.jms.JMSException: MQJMS1016: an internal error has occurred. Please contact your system administrator. Detail: {0}
at com.ibm.mq.jms.services.ConfigEnvironment.newException(ConfigEnvironment.java:540)
at com.ibm.mq.jms.MQQueueAgentThread.run(MQQueueAgentThread.java:1583)
at java.lang.Thread.run(Thread.java:568)
---- Begin backtrace for Nested Throwables
java.lang.NullPointerException
at com.ibm.mq.jms.MQQueueAgentThread.processMessage(MQQueueAgentThread.java:368)
at com.ibm.mq.jms.MQQueueAgentThread.run(MQQueueAgentThread.java:1557)
at java.lang.Thread.run(Thread.java:568)

[8/9/05 19:55:14:576 EDT] 2a50db6e JMSExceptionL E WMSG0057E: Error on JMSConnection for MDB MSSPriceChangeAlertMDB , JMSDestination jms/MarketDataQueue , JMS Linked Exception : java.lang.NullPointerException
at com.ibm.mq.jms.MQQueueAgentThread.processMessage(MQQueueAgentThread.java:368)
at com.ibm.mq.jms.MQQueueAgentThread.run(MQQueueAgentThread.java:1557)
at java.lang.Thread.run(Thread.java:568)

[8/9/05 19:55:14:654 EDT] 2a50db6e MDBListenerIm I WMSG0043I: MDB Listener MarketDataAlertListener stopped for JMSDestination jms/MarketDataQueue
[8/9/05 19:55:14:982 EDT] 234d1b6e ServerSession W WMSG0031E: Exception processing JMS Message for MDB MSSPriceChangeAlertMDB, JMSDestination jms/MarketDataQueue : javax.ejb.TransactionRolledbackLocalException: ; nested exception is: com.ibm.ws.exception.WsEJBException
com.ibm.ws.exception.WsEJBException
at com.ibm.ejs.container.LocalExceptionMappingStrategy.mapException(LocalExceptionMappingStrategy.java:159)
at com.ibm.ejs.container.LocalExceptionMappingStrategy.mapCSITransactionRolledBackException(LocalExceptionMappingStrategy.java:293)
at com.ibm.ejs.container.EJSContainer.postInvoke(EJSContainer.java:3128)
at com.ibm.ejs.container.MDBWrapper.onMessage(MDBWrapper.java:102)
at com.ibm.ejs.container.MDBWrapper.onMessage(MDBWrapper.java:127)
at com.ibm.ejs.jms.listener.ServerSession.run(ServerSession.java:372)
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:672)
javax.ejb.TransactionRolledbackLocalException: ; nested exception is: com.ibm.ws.exception.WsEJBException
at com.ibm.ejs.container.LocalExceptionMappingStrategy.mapCSIException(LocalExceptionMappingStrategy.java:96)
at com.ibm.ejs.container.LocalExceptionMappingStrategy.mapException(LocalExceptionMappingStrategy.java:165)
at com.ibm.ejs.container.LocalExceptionMappingStrategy.mapCSITransactionRolledBackException(LocalExceptionMappingStrategy.java:293)
at com.ibm.ejs.container.EJSContainer.postInvoke(EJSContainer.java:3128)
at com.ibm.ejs.container.MDBWrapper.onMessage(MDBWrapper.java:102)
at com.ibm.ejs.container.MDBWrapper.onMessage(MDBWrapper.java:127)
at com.ibm.ejs.jms.listener.ServerSession.run(ServerSession.java:372)
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:672)

Thanks a ton in advance!