my firsApp "HelloWorld" connect was rejected.

Question

FLash cs4 output:

Connecting...
Error #2044: unhandled NetStatusEvent:。 level=error, code=NetConnection.Connect.Rejected
 at HelloWorld/connectHandler()

Server log:

Sat 01:54:17 PM: Core (4072) connection to admin accepted.

----------------connect again----------------------------

Sat 02:09:31 PM: Core (1196) connection to admin accepted.
Sat 02:09:31 PM: Core (1196) sending register cmd to edge.
Sat 02:09:31 PM: Core (1196) socket migration failed.

----------------connect again----------------------------

Sat 02:12:03 PM: Core (1196) socket migration failed.

Here is the code:

HelloWorld.as

package {

 import flash.display.MovieClip;
import flash.net.Responder;
 import flash.net.NetConnection;
 import flash.events.NetStatusEvent;
 import flash.events.MouseEvent;


 public class HelloWorld extends MovieClip {

   // Represents a network connection.
   private var nc:NetConnection;

   // Responder for call to server's serverHelloMsg -- see onReply() below.
   private var myResponder:Responder = new Responder(onReply);


   // Constructor.
   public function HelloWorld() {
   // Set display values.
   textLbl.text = "";
   connectBtn.label = "Connect";

   // Register a listener for mouse clicks on the button.
   connectBtn.addEventListener(MouseEvent.CLICK, connectHandler);
    }


  // When button is pressed, connect to or disconnect from the server.
  public function connectHandler(event:MouseEvent):void {
   if (connectBtn.label == "Connect") {
    trace("Connecting...");

    nc = new NetConnection();

    // Connect to the server.
    nc.connect("rtmp://localhost/HelloWorld");

    // Call the server's client function serverHelloMsg, in HelloWorld.asc.
    nc.call("serverHelloMsg", myResponder, "World");

    connectBtn.label = "Disconnect";

   } else {   
    trace("Disconnecting...");

    // Close the connection.
    nc.close();

    connectBtn.label = "Connect";
    textLbl.text = "";
   }
  }

  // Responder function for nc.call() in connectHandler(). 
  private function onReply(result:Object):void {
            trace("onReply received value: " + result);
   textLbl.text = String(result);
     }

   }
}

---

HelloWorld.asc

// Server-side action taken upon connect request.

application.onConnect = function( client ) {

 // Define new client function for a nc.call().
 client.serverHelloMsg = function( helloStr ) {
  return "Hello, " + helloStr + "!";
 }

 // Accept the connection.
 application.acceptConnection( client );
}