Problem whit multiple movies preloader

programming flash
1

Hy to all, i save this code from some forum, but it has some problem I don´t understand, please can someone look and try it and see if it can solve this out.

thank u all

  
contArr = ["01.swf", "02.swf", "03.swf", "04.swf"];
function preloadClips(nr) {
 var cnt = this.createEmptyMovieClip("container", 10);
 cnt._visible = false;
 var ch = this.createEmptyMovieClip("check", 11);
 ch.onEnterFrame = function() {
  var bl = this._parent.container.getBytesLoaded();
  var bt = this._parent.container.getBytesTotal();
  if (bl/bt == 1) {
   trace("loaded "+contArr[nr]);
   this.removeMovieClip();
   this._parent.container.removeMovieClip();
   if (this.nr<=2) {
	preloadClips(++nr);
   } else {
	trace("COMPLETED");
	//return;
   }
  }
 };
 cnt.loadMovie(contArr[nr]);
}
preloadClips(0);