title: Error #2007: Parameter hitTestObject must be non-null
body: <p>this is my code- it's working and moving to frame 3 but everything is stuck there and I 
  get this Error #2007</p>
  
  <pre><code>function createMC(event:Event):void 
  {
    var hasa_mc:MovieClip= new hasa();
    stage.addChild(hasa_mc);
    var halfMc:int=hasa_mc.width/2;
    hasa_mc.x=randomNum(70+halfMc,480-halfMc);
    hasa_mc.addEventListener(Event.ENTER_FRAME, abc);
    hasa_mc.addEventListener(Event.ENTER_FRAME, dropCheckHit);
  
    function dropCheckHit(event:Event):void 
    {
      if (hasa_mc.hitTestObject(hauta1_mc)) {
          hasa_mc.removeEventListener(Event.ENTER_FRAME, dropCheckHit);
          event.target.parent.removeChild(event.target);
          countertime++;
          score_txt.text=String(countertime*10)
  
  
          if (countertime==10)
          {
      gotoAndStop(3);
  
      }
  </code></pre>