Kirupa XML Photogallery question...everybody say it's easy but nobody can solve it

1

Hi I’ve try to ask this question to all my friends that do flash but they all say it’s easy but nobody gave me an answer and i starting to think it’s not that easy at all.
I am trying to get the preview button disappear when the first pic is loaded and the next button disappear when the last pics is loaded in the kirupa xml flash gallery.
I can’t do it at all , i am just a beginner and i was wondering if any of you guys have an idea what to do, maybe this script can’t be chance in order to do that.
Thanks alot
this is the code:
var tcount =0
function loadXML(loaded) {
if (loaded) {
xmlNode = this.firstChild;
image = [];
description = [];
thumbnails = [];
total = xmlNode.childNodes.length;
for (i=0; i<total; i++) {
image* = xmlNode.childNodes*.childNodes[0].firstChild.nodeValue;
description* = xmlNode.childNodes*.childNodes[1].firstChild.nodeValue;
thumbnails* = xmlNode.childNodes*.childNodes[2].firstChild.nodeValue;

    }
    firstImage();
     thumbnails_fn(tcount);
} else {
    content = "file not loaded!";
}

}
preloader.preload_bar._xscale=0
xmlData = new XML();
xmlData.ignoreWhite = true;
xmlData.onLoad = loadXML;
xmlData.load(“Images.xml”);
/////////////////////////////////////
listen = new Object();
listen.onKeyDown = function() {
if (Key.getCode() == Key.LEFT) {
prevImage();
} else if (Key.getCode() == Key.RIGHT) {
nextImage();
}
};
Key.addListener(listen);
previous_btn.onRelease = function() {
prevImage();
};
next_btn.onRelease = function() {
nextImage();
};
/////////////////////////////////////
p = 0;

function stuff() {
preloader._visible = true;
var filesize = picture.getBytesTotal();
var loaded = picture.getBytesLoaded();

preloader.preload_bar._xscale = 100*loaded/filesize;

if (picture._width) {
    picture._x = bgd._x-picture._width/2;
    picture._y = bgd._y-picture._height/2;
    preloader._visible = false;
    bgd._width += (picture._width+10-bgd._width)/3;
    bgd._height += (picture._height+10-bgd._height)/3;
    if (Math.abs(bgd._width-picture._width-10)&lt;5) {
        bgd._height = picture._height+10;
        bgd._width = picture._width+10;
        picture._alpha += 10;
        if (picture._alpha&gt;100) {
            delete this.onEnterFrame;
            preloader.preload_bar._xscale=0
        }
    }
}

}
function nextImage() {
if (p<(total-1)) {
p++;
picture._alpha = 0;
picture.loadMovie(image[p], 1);
_root.onEnterFrame = stuff;
desc_txt.text = description[p];
picture_num();
}
}
function prevImage() {
if (p>0) {
p–;
picture._alpha = 0;
picture.loadMovie(image[p], 1);
_root.onEnterFrame = stuff;
desc_txt.text = description[p];
picture_num();
}
}
function firstImage() {

    picture._alpha = 0;
    picture.loadMovie(image[0], 1);
    _root.onEnterFrame = stuff;
    desc_txt.text = description[0];
    picture_num();

}
function picture_num() {
current_pos = p+1;
pos_txt.text = current_pos+"/"+total;
}
this.createEmptyMovieClip(“tscroller”, 1000);
scroll_speed = 10;
var tot = 0;
tscroller.onEnterFrame = function() {
if ((_root._ymouse>=thumbnail_mc._y) && (_root._ymouse<=thumbnail_mc._y+thumbnail_mc._height)) {
if (_root._xmouse>=(hit_right._x-40)) {
for (var obj in cliparray) {
cliparray[obj]._x -= scroll_speed;
}
trace(cliparray[0]._x);
if (cliparray[0]._x<-cliparray[0]._width) {
cliparray[0]._x = cliparray[cliparray.length-1]._x+cliparray[cliparray.length-1]._width+5;
var j = cliparray.splice(0, 1);
cliparray = cliparray.concat(j);
}
} else if (_root._xmouse<=(hit_left._x+40)) {
for (var obj in cliparray) {
cliparray[obj]._x += scroll_speed;
}
if (cliparray[cliparray.length-1]._x>250) {
trace(cliparray[0]._x)
cliparray[cliparray.length-1]._x = cliparray[0]._x-(cliparray[cliparray.length-1]._width+5);
var j = cliparray.splice(cliparray.length-1, 1);
cliparray = j.concat(cliparray);
}
}
}
};
cliparray=[]
function checkloaded(k){
trace(k)
if(k<image.length-1){
k++
thumbnails_fn(k)
}
}
function thumbnails_fn(k) {
var yy = thumbnail_mc.createEmptyMovieClip(“t”+k, thumbnail_mc.getNextHighestDepth());
tlistener = new Object();
tlistener.onLoadInit = function(target_mc) {
cliparray.push(target_mc);
target_mc._x = 5+(target_mc._width+5)*k;
target_mc.pictureValue = k;
tot += target_mc._x;
target_mc.onRelease = function() {
p = this.pictureValue-1;
nextImage();
};
target_mc.onRollOver = function() {
this._alpha = 50;
thumbNailScroller();
};
target_mc.onRollOut = function() {
this._alpha = 100;
};
checkloaded(k)
};
image_mcl = new MovieClipLoader();
image_mcl.addListener(tlistener);
image_mcl.loadClip(thumbnails[k], “thumbnail_mc.t”+k);
}