Flash XML error

I'm using the following code to get something through XML

var myLoader:URLLoader;
var myXML:XML;
var myXMLURL:URLRequest = new URLRequest("http://testapp.varheroes.com/yofacebook/canvas/calcammo/");

myXMLURL.method = URLRequestMethod.POST;
myLoader= new URLLoader(myXMLURL);
myLoader.dataFormat=URLLoaderDataFormat.TEXT;
myLoader.addEventListener(Event.COMPLETE, processXML);


function processXML(e:Event):void {
    myXML = new XML(e.target.data);
    dummyText.text = myXML.AMMO;
}

When I t开发者_如何学运维est the code offline it works perfectly fine but when I put it on the webpage

http://media.varheroes.com/flash/as3.swf

It stops working :/

Running it offline gives me this XML, which I can put in a text field

<MAIN><AMMO>54564564564564564545464564564564</AMMO></MAIN>

Look for cross domain xml if your xml file is out of your application.