Subscriber does not receive data from MDB

[janm]

The mapMessage.getString() is allways null in the following run method of a Thread. The same in the MDB direct outputs data.

public void run() {
 while (true) {
 try{
 System.out.println("run...");
 Message msg = getSubscriber().receive(0);
 MapMessage mapMessage = (MapMessage) msg;
 String rssfeed = mapMessage.getString("rssfeed");
 this.applet.rssfeed = rssfeed;
 System.out.println("feed: " + rssfeed);
 }catch(Exception e){
 e.printStackTrace();
 }

 applet.repaint();
 }
}

There is a Warning-message if JBoss4 starts:
16:13:00,379 WARN [JMSContainerInvoker] Could not find the topic destination-jndi-name=topic/RssTopic

The JBoss Console entries are like:
jndiName=local/RssMessageBean@12974590,plugin=pool,service=EJB
jndiName=local/RssMessageBean@12974590,service=EJB

Don't know if the MDB is registered correct?

EJB

<message-driven>
 <ejb-name>RssMessageBean</ejb-name>
 <ejb-class>ejb.RssMessageBean</ejb-class>
 <transaction-type>Container</transaction-type>
 <acknowledge-mode>Auto-acknowledge</acknowledge-mode>
 <message-driven-destination>
 <destination-type>javax.jms.Topic</destination-type>
 <subscription-durability>NonDurable</subscription-durability>
 </message-driven-destination>
 </message-driven>

JBoss XML

<message-driven>
 <ejb-name>RssMessageBean</ejb-name>
 <configuration-name>Standard Message Driven Bean</configuration-name>
 <destination-jndi-name>topic/RssTopic</destination-jndi-name>
 </message-driven>