Running problem and #2007 null error

1

Hi,

I’ve created a box, which has a zoom in/out motion, also has got submenu box on it when cursor is on.
Here is the sample:
http://yum.moo.jp/050208/02bup.html

CODE:



package {
	
	import flash.events.Event;
	import flash.display.MovieClip;

	
	public class DCbtn {
		private var _clip:MovieClip;
		 var btn01:robtn01;
		


		public function DCbtn(clip:MovieClip) {  
		
		_clip = clip;
		
		_clip.addEventListener(Event.ENTER_FRAME,onLoaded);
		_clip.buttonMode = true;
		}


public function onLoaded(event:Event):void {



	if(_clip.hitTestPoint(_clip.stage.mouseX,_clip.stage.mouseY,true)){

		trace("ok!");
		scscale(1,0.7,0.5);
		//window.addChild(DisplayObject(sc01));
		 btn01 = new robtn01();
		_clip.addChild(btn01);
		//btn01.alpha = 1;
		btn01.x = -100;
		btn01.y = -70;
		
		
	}
	else{
		trace("ok too!");	
		scscale(0.85,0.7,0.3);
		_clip.removeChild(btn01);
		//btn01.alpha = 1;


	}
}


function scscale(mScale,acc,conv) {
	var theScale:Number = 0;
	//theScale = new Number();

		theScale = theScale*acc+(mScale- _clip.scaleY)*conv;
		_clip.scaleX = _clip.scaleY += theScale;
		}


}}

But something is wrong…
If I keep running it, the speed is getting very slow, and sometimes it freezes…
Also there is en error message like “Error #2007: Parameter text must be non-null”

I checked some articles and assumed “stage” setting on my .as causes this null error, but I don’t know how I can fix it… probably it causes the running speed problem as well?
Is there any better code to create such kind of button box?

Please somebody help me!