PopUpWindow reference and null object

I have been struggling with this issue for the past few hours but still have no idea what happened. Here's the script:

An application built on top of the Mate framework sometimes needs to communicate with a remote server over a simple binary socket.

When receiving a specific package, I need to switch the view (using the ViewStack) and create a custom panel (using the PopUpManager class). This custom panel contains a dataGrid component that needs to be populated with some XML received along with the specified package.

The problem is that when I try to assign the XML DataGrid to the dataProvider, I keep getting the error "Can't access properties or method of null object reference". The only thing I can think of is some kind of race in event handling and component creation.

Here are the most interesting code snippets:

<!-- LoginEvent.LOGIN_OK _____________________________________________________________________ -->

<EventHandlers type="{LoginEvent.LOGIN_OK}">

    <MethodInvoker generator="{UserManager}" method="storeCurrentUser" arguments="{event.fullName}"/>
    <EventAnnouncer generator="{NavigationEvent}" type="{NavigationEvent.MAIN}"/>
    <MethodInvoker generator="{CustomSocket}" method="listBoards"/>

      

        
        
        
      

    

In the above code, I am responding to receiving the LOGIN_OK package.

Save your custom data, change the view, and ask the Socket to send the request (the response for this request is our verySpecificPacket )

Here's the details on how I change the view and create a custom tooltip. In MainUI.mxml:

<mate:Listener type="{NavigationEvent.MAIN}"    method="handleNavigationEvent" />

private function launchBoardListWindow():void {
   Logger.info("launchBoardListWindow()");
   var win:BoardList = PopUpManager.createPopUp(this, BoardList, true) as BoardList;
   PopUpManager.centerPopUp(win);
}

private function handleNavigationEvent(event:NavigationEvent):void {

   viewStack.selectedIndex = MAIN;
   launchBoardListWindow();
}

      

        
        
        
      

    

The third position in EventMap is not important, just ask the socket packaging to send some kind of packet. The server is supposed to respond with a verySpecialPacket along with the XML payload. And here we are in the part where the error is. In the mxml describing my custom panel, I am setting a listener for the event that is dispatched after my verySpecialPacket is received .

public function handleListBoardsEvent(e:ListBoardsEvent):void {

   Logger.info("handleListBoardsEvent");        
   xmlData = e.xml;     
   boardList.dataProvider = xmlData.children(); // Here the error!!!
}

      

        
        
        
      

    

I really don't get it as xmlData is ok and a custom panel was created with all child components. Thanks for reading!