i'm trying to do an image gallery. initially i was not able to display the thumbnails stored in the array. instead it keep showing the same thumbnails. with that solve i'm facing another problem.. i'm keep getting an error Error #2044: Unhandled ioError:. text=Error #2124: Loaded file is an unknown type. when i click on the thumbnail to load the .txt file.

hw can i command the pre-loader to track the progress of the download? 

```
 public function loadImage(filename:String):void
        {
            // show the preloader
            preloader.visible = true;

    // set the source to the UILoader to the full size image to load and display

            addChild(preloader);

            // command the preloader to track the progress of the download
            var loadWindow:UILoader;    
        preloader.trackLoading("LOADING: " + (loader*100).toFixed(0) + "%");

        }

```