Error #2007: Parameter hitTestObject must be non-null - actionscript-3

Question

this is my code- it's working and moving to frame 3 but everything is stuck there and I
get this Error #2007
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);
}

Answer 1

The error code and description refers to the line:
if (hasa_mc.hitTestObject(hauta1_mc)) {
My guess would be the movieclip hauta1_mc does not exist on frame 3 of your movie, so once you go to frame 3 and your dropCheckHit function executes the null reference error is thrown.
To resolve you can remove the enter frame listener and stop checking if the movieclip has been hit:
if (countertime==10)
{
hasa_mc.removeEventListener(Event.ENTER_FRAME, dropCheckHit);
gotoAndStop(3);
}
Note: You may need to remove the other listener you have on hasa_mc as well if hasa_mc does not exist in frame 3.

Answer 2

thank you. from where i need to remove also ? still does not works.
when it goes to frame 3 there is new MC that hit new object
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);
hasa_mc.removeEventListener(Event.ENTER_FRAME, dropCheckHit);
}
hauta1_mc.nextFrame();}
else if (hasa_mc.y > 380)
{
xdirection = 0;
ydirection = 0;
hasa_mc.x = 190;
hasa_mc.y = 200;
hauta1_mc.x=220;
lifeCounter--; //
life_txt.text=String(lifeCounter);
trace(lifeCounter);
if (lifeCounter==0)
{
gotoAndStop(5);
}
}
}
}