The question about propagate pipe

Hi,  
I have a problem with propagate pipe. I create a server, server is used to send message to multiple receiver. The following is my pipe advertisement. 

<?xml version="1.0" encoding="Big5"?>
<jxta:PipeAdvertisement>
 <Name>JXTACHAT</Name>
 <Id>urn:jxta:uuid-59616261646162614E504720503250338918BB40B3D94F00AB019C67D54254DB04</Id>
 <Type>JxtaPropagate</Type>
 <Description>JXTACHAT</Description>
</jxta:PipeAdvertisement>

The following is my server program (major part) : 

private void startJxta()
{
       group = PeerGroupFactory.newNetPeerGroup();

        groupAdvertisement = group.getPeerGroupAdvertisement();

        displayArea.append("getting Discovery Service…\n");
        discovery = group.getDiscoveryService();
        displayArea.append("getting Pipe Service…\n");
        pipes = group.getPipeService();
        startServer();
}
private void startServer()
{
        displayArea.append("starting service …\n");
        gid = group.getPeerGroupID();
        displayArea.append("read PropogateOut.adv…\n");
        PipeAdvertisement pipeadv = null;

        FileInputStream is = new FileInputStream("PropogateOut.adv");
                pipeadv = (PipeAdvertisement)
                          AdvertisementFactory.newAdvertisement(
                              new MimeMediaType("text/xml"), is);
                is.close();

        displayArea.append("publish pipe adv…\n");
        discovery.publish(pipeadv, DiscoveryService.ADV);
        discovery.remotePublish(pipeadv, DiscoveryService.ADV);

         displayArea.append("create Output pipe…\n");
        
        myOutputPipe = pipes.createOutputPipe(pipeadv, 30000);
        displayArea.append("pipe id is：" + pipeadv.getPipeID() +" \n");
        while(true)
        {
            msg = new Message();
            StringMessageElement sme = new StringMessageElement("DataTag", "Its for test", null);
            msg.addMessageElement(null, sme);
            myOutputPipe.send(msg);

            MessageElement msgElement = msg.getMessageElement(null, "DataTag"); 
 
           Thread.sleep(3000);
      }
  
 }

The following is my receiver program (major part) :

private void startJxta() 
{
    netPeerGroup = PeerGroupFactory.newNetPeerGroup();
    groupAdvertisement = netPeerGroup.getPeerGroupAdvertisement();
    displayArea.append("getting Discovery Service…\n");
    discovery = netPeerGroup.getDiscoveryService();
    displayArea.append("getting  Pipe Service…\n");
    pipes = netPeerGroup.getPipeService();
    startClient();
}

 private void startClient()
 {
        displayArea.append("finding Service adv.…\n");
        Enumeration en = null;
        while (true)
         {
            try {
                      displayArea.append("local searching …\n");
                en = discovery.getLocalAdvertisements(DiscoveryService.ADV 
                                                    , "Name"
                                                    , "JXTACHAT");

                    if ((en != null) && en.hasMoreElements()) {
                        break;
                    }

                  displayArea.append("remote searching …\n");
                discovery.getRemoteAdvertisements(null
                                              , DiscoveryService.ADV
                                              , "Name"
                                              , "JXTACHAT",1, null);
                        try { 
                                Thread.sleep(2000);
                        } catch (Exception e) {}

            }
            catch (IOException e) {}
        }

        displayArea.append("getting service advertisement！\n");

        try
         {
                PipeAdvertisement pipeadv2 = (PipeAdvertisement) en.nextElement();

                displayArea.append("create Input Pipe…" +pipeadv2.getPipeID()+ "…\n");
                myInputPipe = pipes.createInputPipe(pipeadv2, this); 

        } catch (Exception e) {
            e.printStackTrace();
            displayArea.append("Input Pipe fail");
        }
}
 //----------------------wait for message
public void pipeMsgEvent(PipeMsgEvent event)
{
        try
        {
            msg = event.getMessage();
            if(msg == null)
             {
                displayArea.append("msg is null…\n");
                return;
            }
        }
        catch(Exception e)
        {
            e.printStackTrace();
            return;
        }

        Message.ElementIterator en = msg.getMessageElements();
        if(!en.hasNext())
            return;
        MessageElement msgElement = msg.getMessageElement(null, "DataTag");
        if(msgElement.toString() == null)
            displayArea.append("message is null\n");
        else
            displayArea.append("the message is：" + msgElement.toString() + "\n");
 }

I don't know why my receiver cann't receive the message that server sended.  

Does anyone can tell me how to solve this problem ?

Thanks!