Our application deployed as one EAR file contains two MDB.
The queues are defined in $JBOSS_HOME/deploy/hornetq/mbi2e-lafr-sb2000-ipc-hornetq-jms.xml:
<?xml version="1.0" encoding="UTF-8"?>
<configuration xmlns="urn:hornetq"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="urn:hornetq /schema/hornetq-jms.xsd">
<queue name="mbi2e-lafr-sb2000-ipc/MessageDistributorQueue">
<entry name="queue/mbi2e-lafr-sb2000-ipc/MessageDistributorQueue"/>
</queue>
<queue name="mbi2e-lafr-sb2000-ipc/SalesOrderImportQueue">
<entry name="queue/mbi2e-lafr-sb2000-ipc/SalesOrderImportQueue"/>
</queue>
</configuration>

If I first startup JBossAS, already including the queue definitions shown above, and then deploy my ear file everything is fine. No Errors.

But if I bounce and restart the engine after that, with everything deployed, I get Warnings and Errors.

Right after the start of the MDB listening on the 'MessageDistributorQueue' I get this:
11:48:58,754 WARN [HornetQActivation] Failure in HornetQ activation org.hornetq.ra.inflow.HornetQActivationSpec(ra=org.hornetq.ra.HornetQResourceAdapter@1fe97f9 destination=queue/mbi2e-lafr-sb2000-ipc/MessageDistributorQueue destinationType=javax.jms.Queue ack=Auto-acknowledge durable=false clientID=null user=null maxSession=15): HornetQException[errorCode=105 message=Unable to validate user: null for check type CONSUME for address jms.queue.mbi2e-lafr-sb2000-ipc/MessageDistributorQueue]
at org.hornetq.core.protocol.core.impl.ChannelImpl.sendBlocking(ChannelImpl.java:287) [:]
at org.hornetq.core.client.impl.ClientSessionImpl.internalCreateConsumer(ClientSessionImpl.java:1556) [:]
at org.hornetq.core.client.impl.ClientSessionImpl.createConsumer(ClientSessionImpl.java:447) [:]
at org.hornetq.core.client.impl.ClientSessionImpl.createConsumer(ClientSessionImpl.java:392) [:]
at org.hornetq.core.client.impl.DelegatingSession.createConsumer(DelegatingSession.java:201) [:]
at org.hornetq.ra.inflow.HornetQMessageHandler.setup(HornetQMessageHandler.java:165) [:]
at org.hornetq.ra.inflow.HornetQActivation.setup(HornetQActivation.java:291) [:]
at org.hornetq.ra.inflow.HornetQActivation$SetupActivation.run(HornetQActivation.java:573) [:]
at org.jboss.resource.work.WorkWrapper.run(WorkWrapper.java:172) [:6.0.1-SNAPSHOT]
at org.jboss.threads.SimpleDirectExecutor.execute(SimpleDirectExecutor.java:33) [:2.0.0.CR7]
at org.jboss.threads.QueueExecutor.runTask(QueueExecutor.java:801) [:2.0.0.CR7]
at org.jboss.threads.QueueExecutor.access$100(QueueExecutor.java:45) [:2.0.0.CR7]
at org.jboss.threads.QueueExecutor$Worker.run(QueueExecutor.java:821) [:2.0.0.CR7]
at java.lang.Thread.run(Thread.java:662) [:1.6.0_23]
at org.jboss.threads.JBossThread.run(JBossThread.java:122) [:2.0.0.CR7]

And then a few more times during the further startup process I see this:
11:49:00,759 INFO [HornetQActivation] Attempting to reconnect org.hornetq.ra.inflow.HornetQActivationSpec(ra=org.hornetq.ra.HornetQResourceAdapter@1fe97f9 destination=queue/mbi2e-lafr-sb2000-ipc/MessageDistributorQueue destinationType=javax.jms.Queue ack=Auto-acknowledge durable=false clientID=null user=null maxSession=15)
11:49:00,998 ERROR [HornetQActivation] Unable to reconnect org.hornetq.ra.inflow.HornetQActivationSpec(ra=org.hornetq.ra.HornetQResourceAdapter@1fe97f9 destination=queue/mbi2e-lafr-sb2000-ipc/MessageDistributorQueue destinationType=javax.jms.Queue ack=Auto-acknowledge durable=false clientID=null user=null maxSession=15): HornetQException[errorCode=105 message=Unable to validate user: null for check type CONSUME for address jms.queue.mbi2e-lafr-sb2000-ipc/MessageDistributorQueue]
at org.hornetq.core.protocol.core.impl.ChannelImpl.sendBlocking(ChannelImpl.java:287) [:]
at org.hornetq.core.client.impl.ClientSessionImpl.internalCreateConsumer(ClientSessionImpl.java:1556) [:]
at org.hornetq.core.client.impl.ClientSessionImpl.createConsumer(ClientSessionImpl.java:447) [:]
at org.hornetq.core.client.impl.ClientSessionImpl.createConsumer(ClientSessionImpl.java:392) [:]
at org.hornetq.core.client.impl.DelegatingSession.createConsumer(DelegatingSession.java:201) [:]
at org.hornetq.ra.inflow.HornetQMessageHandler.setup(HornetQMessageHandler.java:165) [:]
at org.hornetq.ra.inflow.HornetQActivation.setup(HornetQActivation.java:291) [:]
at org.hornetq.ra.inflow.HornetQActivation.handleFailure(HornetQActivation.java:539) [:]
at org.hornetq.ra.inflow.HornetQActivation$SetupActivation.run(HornetQActivation.java:577) [:]
at org.jboss.resource.work.WorkWrapper.run(WorkWrapper.java:172) [:6.0.1-SNAPSHOT]
at org.jboss.threads.SimpleDirectExecutor.execute(SimpleDirectExecutor.java:33) [:2.0.0.CR7]
at org.jboss.threads.QueueExecutor.runTask(QueueExecutor.java:801) [:2.0.0.CR7]
at org.jboss.threads.QueueExecutor.access$100(QueueExecutor.java:45) [:2.0.0.CR7]
at org.jboss.threads.QueueExecutor$Worker.run(QueueExecutor.java:821) [:2.0.0.CR7]
at java.lang.Thread.run(Thread.java:662) [:1.6.0_23]
at org.jboss.threads.JBossThread.run(JBossThread.java:122) [:2.0.0.CR7]

At the very end of the startup process connect succeeds:
2010-12-28 11:49:09,133 INFO [org.hornetq.ra.inflow.HornetQActivation.info] (pool-1-thread-2) Attempting to reconnect org.hornetq.ra.inflow.HornetQActivationSpec(ra=org.hornetq.ra.HornetQResourceAdapter@1fe97f9 destination=queue/mbi2e-lafr-sb2000-ipc/SalesOrderImportQueue destinationType=javax.jms.Queue ack=Auto-acknowledge durable=false clientID=null user=null maxSession=15)
2010-12-28 11:49:09,156 INFO [org.hornetq.ra.inflow.HornetQActivation.info] (pool-1-thread-1) Attempting to reconnect org.hornetq.ra.inflow.HornetQActivationSpec(ra=org.hornetq.ra.HornetQResourceAdapter@1fe97f9 destination=queue/mbi2e-lafr-sb2000-ipc/MessageDistributorQueue destinationType=javax.jms.Queue ack=Auto-acknowledge durable=false clientID=null user=null maxSession=15)
2010-12-28 11:49:09,236 INFO [org.apache.coyote.http11.Http11Protocol.start] (Thread-2) Starting Coyote HTTP/1.1 on http-0.0.0.0-8080
2010-12-28 11:49:09,241 INFO [org.apache.coyote.http11.Http11Protocol.start] (Thread-2) Starting Coyote HTTP/1.1 on http-0.0.0.0-8443
2010-12-28 11:49:09,243 INFO [org.jboss.bootstrap.impl.base.server.AbstractServer.run] (Thread-2) JBossAS [6.0.1.SNAPSHOT "Neo"] Started in 3m:57s:688ms
2010-12-28 11:49:09,259 INFO [org.hornetq.ra.inflow.HornetQActivation.info] (pool-1-thread-1) Reconnected with HornetQ
2010-12-28 11:49:09,292 INFO [org.hornetq.ra.inflow.HornetQActivation.info] (pool-1-thread-2) Reconnected with HornetQ