[CREDO]

var loads:MovieClipLoader = new MovieClipLoader();
var listener:Object = {};
loads.addListener(listener);
listener.onLoadStart = function():Void  {
	preloader_mc._visible = true;
};
listener.onLoadProgress = function(loader_mc:MovieClip, a:Number, b:Number):Void  {
	var c:Number = a/b;
	preloader_mc.line_mc._xscale = c*100;
	preloader_mc.percent_txt.text = Math.floor(c*100);
};
listener.onLoadComplete = function():Void  {
	preloader_mc._visible = false;
};

и клипы грузишь уже так


loads.LoadClip(".swf", target)