[flexcoders] Error after loading swf

[tonyx_788]

Hi all, i get this error Error: Unable to load ''. after loading a swf
  and my app just stops working
here is part of my code.


*****************************main mxml

 private function ShowPano():void
 {
  var SWFLoaderInstance:Panoramica2 =
        Panoramica2(PopUpManager.createPopUp(this,Panoramica2,true));//
instantiate and show the title window

  PopUpManager.centerPopUp(SWFLoaderInstance);
  SWFLoaderInstance.mainAppPano = this  //Reference to the main app
scope
  }

*******************************Panoramica2

<?xml version="1.0" encoding="utf-8"?>
<mx:Canvas xmlns:mx="http://www.adobe.com/2006/mxml";
creationComplete="doInt()"
        cornerRadius="10" width="600" height="450">
<mx:Script><![CDATA[
        import mx.controls.PopUpMenuButton;
        import mx.managers.PopUpManager;
        import mx.collections.ArrayCollection;
        import mx.controls.Button;

 [Bindable]public var mainAppPano:Object = null;
//called by the close event raised byclicking the close button
 private function closeWindow():void
 {
   PopUpManager.removePopUp(this);
 }//closeWindow
 private function doInt():void
 {
 PopUpManager.centerPopUp(this);
 }
]]>
</mx:Script>
        <mx:TitleWindow layout="absolute" right="10" left="10"
showCloseButton="true"
                 close="closeWindow()" top="10" bottom="10">
                <mx:SWFLoader
source="{mainAppPano.datagrid.selectedItem.pano..src}"
scaleContent="false"
                 horizontalCenter="0" verticalCenter="0"/>
        </mx:TitleWindow>

</mx:Canvas>

********************************xml structure
<catalog>

<book>
                <name><![CDATA[<b>Biblioteca Central </b> ]]></name>
                <desc><![CDATA[Se inauguró el 20 de noviembre de 1978
]]></desc>
                <imagen>FOTOS/est/Biblioteca Central Manuel Bartlett
Bautista.jpeg</
imagen>
                <pano nombrePano="Biblioteca Central Bautista">
<src>FOTOS/Panoramicas/PanoZoom642007.swf</src>
</pano>
                <ico>BOTONES/gifs/video.gif</ico>
                <video nombreVid="Biblioteca Manuel Bartlet">
<src>VIDEOS/Biblioteca Manuel Bartlet.flv</src>
</video>
                <audio/>
                <pie>Biblioteca Central Manuel Bartlett Bautista</pie>
        </book>

</catalog>