loadClip método problemas

 
var mcl:MovieClipLoader = new MovieClipLoader();
 
mclL.onLoadProgress = function(target, loaded, total) {
  temp = Math.round((loaded/total) * 100);
  loader.percent.text = temp + "%";
  loader.progressBar._width = temp;
}
 
mclL.onLoadInit = function() {
  loader._visible = false;
  loader.percent.text = "";
  temp = 0;
  loader.progressBar._width = temp;
}
 
mcl.addListener(mclL);
 
mcl.loadClip('my_clip.swf?param=false', holder);
 

var Xpos:Number=22;
var Ypos:Number=162;
var swf:MovieClip;
var loader:Loader=new Loader();

var defaultSWF:URLRequest=new URLRequest("Destination_Folder/filename.swf");

loader.load(defaultSWF);
loader.x=Xpos;
loader.y=Ypos;
addChild(loader);
//////////////////////////////////////////////////////////////////////////////

//Buttons Universal functions
function btnClick(event:MouseEvent):void{
    
    removeChild(loader);
    var newSWFRequest:URLRequest=new URLRequest("Destination_Folder/"+event.target.name+".swf");
    loader.load(newSWFRequest);
    loader.x=Xpos;
    loader.y=Ypos;
    addChild(loader);
}
//Buttons Listener
Btn.addEventListener(MouseEvent.CLICK,btnClick);