Fading stops working on thumbnails/main images?

1

Hey got the fading working on an xml driven gallery i made, but after clicking the images a few times the fade effect gets faster and faster and eventually stops working, can anyone see where ive gone wrong??? any help greatly appreciated!

link to test file:

http://lauriedeandrivingschool.co.uk…gal/xgalv2.swf

code: (all in one frame)

var showVar = new Number();
var fadeDone = new Boolean();
showVar = 0;

function unfadeImage(target_mc:MovieClip):Boolean {
    fadeDone = false;
    if (fadeDone == false) {
        target_mc._alpha += 3;
    }
    if (target_mc._alpha>=100) {
        target_mc._alpha = 100;
        fadeDone = true;
        target_mc._visible = true;
        clearInterval(alpha_interval);
        showVar = 1;
    }
    return fadeDone;
}

_global.thumbRefArray = new Array();
_global.thumbRefArray2 = new Array();
var loader = new MovieClipLoader();
var listener = new Object();
var currentThumb = new String();
var index = new Number();

var my_fmt = new TextFormat(); 
my_fmt.align = "center";
my_fmt.font = "Arial";
my_fmt.size = 9;

index = 0;

listener.onLoadStart = function(target_mc:MovieClip) {
    target_mc._alpha = 0;
    target_mc.createTextField("loadTxt", 1, 3, 16, 70, 25);
    target_mc.loadTxt.setNewTextFormat(my_fmt);
    target_mc.loadTxt.text = "Loading.."
    index ++
};

listener.onLoadProgress = function(target_mc:MovieClip, bytesLoaded:Number, bytesTotal:Number) {
    target_mc.loadTxt.text = "(" +  bytesLoaded + "/" + bytesTotal + ")";
}

listener.onLoadComplete = function(target_mc:MovieClip) {
    target_mc.loadTxt.removeTextField();
    //clearInterval(alpha_interval);
    if (target_mc <> this.mainLoader) {
        do {
            fadeDone = unfadeImage(target_mc);
            var alpha_interval:Number = setInterval(unfadeImage, 5, target_mc);
        } while (fadeDone = false)
    } else {
        this.mainLoader._alpha = 0;
        clearInterval(alpha_interval);
        do {
            fadeDone = unfadeImage(target_mc);
            var alpha_interval:Number = setInterval(unfadeImage, 5, this.mainLoader);
        } while (fadeDone = false)
    }
    //captionTxt.text = "Loading complete"
};

this.nxtBtn._visible = false;
this.prevBtn._visible = false;
this.pgCount.text = "Page 1/2";

myPhoto = new XML();
myPhoto.ignoreWhite = true;
myPhoto.onLoad = function(success) {
    //portfolioTag = this.firstChild;
    numimages = this.firstChild.childNodes.length;
    for (i = 0; i < numimages; i++) {
        _global.thumbRefArray.push("_level0.thumbLoader.thumbnail" + i);
        _global.thumbRefArray2.push("_level0.thumbLoader.thumbnail" + i + ".thumbnail_image");
    }
    var maxPerPage:Number = 15;
    if (numimages <= 15) {
        maxPerPage = numimages;
    } else {
        nxtBtn._visible = true;
    }
    var cols:Number = 4;
    var spacer:Number = 5;
    var thumbW:Number = 65;
    var thumbH:Number = 50;
    loader.addListener(listener);
    for (i=0; i < maxPerPage; i++) {
        this.picHolder = this.firstChild.childNodes*;
        this.thumbHolder = thumbLoader.createEmptyMovieClip("thumbnail"+i, i);
        //_global.thumbRefArray.push("_level0.thumbLoader.thumbnail" + i);
        this.thumbLoader = this.thumbHolder.createEmptyMovieClip("thumbnail_image", 0);
        currentThumb = "_level0.thumbLoader.thumbnail" + i + ".thumbnail_image";
        loader.loadClip(this.picHolder.attributes.thmb, "_level0.thumbLoader.thumbnail" + i + ".thumbnail_image");
        this.thumbHolder.title = this.picHolder.attributes.title;
        this.thumbHolder.main = this.picHolder.attributes.main;
        this.thumbHolder._x = Number(thumbW + spacer) * Number(i % cols);
        this.thumbHolder._y = 8;
        //this.thumbHolder._y = Number(thumbH + spacer) * int(i / 3);

        this.thumbHolder.onRelease = function() {
            this.mainLoader._alpha = 0;
            loader.loadClip(this.main, mainLoader);
            captionTxt.text = this.title;
        };
    }
};
myPhoto.load("gallery.xml");

not all this code is relevant btw, i just copied from another gallery i made previously

if anyone can see where im going wrong it would be a great help. im sure its something simple i just cant see it!

ST