Pre-loader is not loading the entire swf

Hi

I am making a preloader for a large flash file (approx 3.5mb) but it only seems to be loading the first scene.

The coding is the following;

Actionscript Code:

stop();
loadingBar._xscale = 1;
var loadingCall:Number = setInterval(preloadSite, 50);
function preloadSite():Void {
    var siteLoaded:Number = _root.getBytesLoaded();
    var siteTotal:Number = _root.getBytesTotal();
    var percentage:Number = Math.round(siteLoaded/siteTotal*100);
    loadingBar._xscale = percentage;
    percentClip.percentDisplay.text = percentage + "%";
    percentClip._x = loadingBar._x + loadingBar._width;
    bytesDisplay.text = "loaded " + siteLoaded + " of " + siteTotal + " bytes";
    if (siteLoaded >= siteTotal) {
        clearInterval(loadingCall);
        gotoAndStop("start");
    }
}

There are 15 scenes with approx 10 images in each so it is a large file size.

Should I look into loading each scene separately or do any of you know the problem with the above loader.