Wierrd white screen before preloader

programming flash
1

I made a preloader but heres the problem, theres a blank white screen for that last untill the preloader makes it to about 24%

can someone help me fix this
heres the 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);
 percentDisplay.text = percentage + "%";
 loadingBar._xscale = percentage;
 bytesDisplay.text = "loaded " + siteLoaded + " of " + siteTotal + " bytes";
 if (siteLoaded >= siteTotal) {
  clearInterval(loadingcall);
  gotoAndPlay(5);
 }
}