External preloader class

1

i have an external preloader class but im having some problems.

public function onProgress(e:ProgressEvent):void {

		var loaded:Number = e.bytesLoaded;
		var total:Number = e.bytesTotal;
		var perc:Number = loaded/total;
		trace(perc + "-----------------");
		preloaderMC.loaderBar.scaleX = perc;

}

basically it cant see the preloaderMC.
i get this error…

1120: Access of undefined property preloaderMC.