AS3: XML slideshow using recursion , not working (Parameter url must be non-null)

programming flash
1

Hello everybody,
I m trying to work on XML slideshow in the recursion way. I got an error
“TypeError: Error #2007: Parameter url must be non-null.”
Please help…

var arr5:Array= new Array();
var arr_no:int;

var img_str:String=“new2.xml”;
var ur1:URLRequest= new URLRequest(img_str);
var urlLoader:URLLoader= new URLLoader(ur1);
var img_loader:Loader;
var img_url_Loader:URLLoader;
urlLoader.load(ur1);
urlLoader.addEventListener(Event.COMPLETE, func27);
function func27(e:Event)
{
var xml:XML= new XML(e.target.data);
var xmlList:XMLList=xml.children();
for (var a:int=0; a<xmlList.length(); a++)
{
trace(xmlList[a].attribute(“thumb”));
arr5.push(xmlList[a].attribute(“thumb”));
}
func31();
}

function func31()
{
    arr_no= arr5.length;
    trace(arr_no); // its working shows 4 which is correct &  has correct url string from XML
    func30(arr_no);
}

function func30(img_no:int)
{
        img_url_Loader= new URLLoader(new URLRequest(arr5[img_no]));
        img_url_Loader.load(new URLRequest(arr5[img_no]));
        img_url_Loader.addEventListener(Event.COMPLETE, func29);
        
    function func29(e:Event)
    {
        trace("Image Loading");
        img_loader= new Loader();
        img_loader.x=100 +20;
        img_loader.y= 200;
        img_loader.load(new URLRequest(arr5[img_no]));
        banr.addChild(img_loader);
    
      var twn1:Tween= new Tween(img_loader, "alpha", None.easeNone , 0,1, 30, false );
      var twn2:Tween= new Tween(img_loader, "alpha", None.easeNone , 1,0, 30, false );
        twn1.start();
        twn2.stop();
        twn1.addEventListener(TweenEvent.MOTION_FINISH, func28);
        function func28(e:TweenEvent)
        {
            twn2.start();
            img_url=img_url-1;
            func30(img_url);
        }
    }
}