Trouble loading external images

1

Hello,

I’m trying to load some PNGs onto the stage and make them move around. However, I can’t seem to grasp Loader. I get this error:

TypeError: Error #1009: Cannot access a property or method of a null object reference.
at Cloud/::imgLoaded()
Here’s the Cloud class that generates it:

package 
{
    import flash.display.Sprite;
    import gs.TweenLite;
    import flash.events.Event;
    import com.gskinner.utils.Rnd;
    import flash.display.Loader;
    import flash.net.URLRequest;
    
    public class Cloud extends Sprite 
    {
        var loader:Loader = new Loader();
        
        function Cloud():void 
        {
            var request:URLRequest = new URLRequest('cloud' + Rnd.integer(1,4) + '.png');
            loader.load(request);
            loader.contentLoaderInfo.addEventListener(Event.COMPLETE, imgLoaded);
        
        }
        
        function imgLoaded(e:Event):void
        {
            this.addChild(e.target.content);
            this.y = Math.random() * 100;
            this.x = Math.random() * 100;
            
            TweenLite.to(this, 2, {x:stage.stageWidth, y:this.y});

            if( this.x <= 0 )
            {
                TweenLite.to(this, 2, {x:stage.stageWidth, y:this.y});
            }
            else if( this.x >= stage.stageWidth ) 
            {
                TweenLite.to(this, 2, {x:0, y:this.y});
            }
        }
        
    } // end class
}

On the first frame of the main timeline I run this:

function populateStage():void
{
    for(var i:int; i < 2; i++)
    {
        var aCloud:Cloud = new Cloud();
        aCloud.y = Math.random() * 100;
        aCloud.x = Math.random() * 100;
    }
}

//stop();
populateStage();

I know a null reference means it’s pointing to nothing, but why is that? My code has it pointing to e.target.content right? Anyone know why I’m getting that error?

Thanks in advance.