TypeError: Error #1009: Cannot access a property or method of a null object reference

[Hurdarr]

Hey all. I checked Google and saw tons of results. Read some of the answers and tried to apply the solutions they used. Either it doesn't work or I'm doing something wrong.

I kinda understand the error, but I don't know how to correct it.

This is what I have in one frame. I know, I know...I'll use classes next time. Promise.

The error only appeared when I implemented the following bit of code:

if(mcBall.hitTestObject(man))
	{
		gotoAndPlay("gameOver");
	}

stop();

// VARIABLES

var ballXSpeed:Number = -8;
var ballYSpeed:Number = -8;

var starXSpeed:Number = 8;
var starYSpeed:Number = 8;

var leftKeyDown:Boolean = false;
var upKeyDown:Boolean = false;
var rightKeyDown:Boolean = false;
var downKeyDown:Boolean = false;

var manSpeed:Number = 7;

// MOVE RED CIRCLE

mcBall.addEventListener(Event.ENTER_FRAME, moveBall);

function moveBall(event:Event):void
{	
	mcBall.x += ballXSpeed;
	mcBall.y += ballYSpeed;
	
	if(mcBall.x >= stage.stageWidth-mcBall.width)
	{
		ballXSpeed *= -1;
	}
	
	if(mcBall.x < 0)
	{
		ballXSpeed *= -1;
	}
	
	if(mcBall.y >= stage.stageHeight-mcBall.height)
	{
		ballYSpeed *= -1;
	}
	
	if(mcBall.y <0)
	{
		ballYSpeed *= -1;
	}	
}


// MOVE STAR

mcStar.addEventListener(Event.ENTER_FRAME, moveStar);

function moveStar(event:Event):void
{	
	mcStar.x += starXSpeed;
	mcStar.y += starYSpeed;
	
	if(mcStar.x >= stage.stageWidth-mcStar.width)
	{
		starXSpeed *= -1;
	}
	
	if(mcStar.x < 0)
	{
		starXSpeed *= -1;
	}
	
	if(mcStar.y >= stage.stageHeight-mcStar.height)
	{
		starYSpeed *= -1;
	}
	
	if(mcStar.y <0)
	{
		starYSpeed *= -1;
	}
	
}

man.addEventListener(Event.ENTER_FRAME, moveMan)

// MOVE PLAYER

function moveMan(event:Event):void
{
	Mouse.hide();
	man.x = mouseX;
	man.y = mouseY;
}


// COLLISION CIRLE AND MAN

// The culprit for messing up

stage.addEventListener(Event.ENTER_FRAME, circleHits);

function circleHits(event:Event):void
{
	if(mcBall.hitTestObject(man))
	{
		gotoAndPlay("gameOver");
	}
}

When the collision occurs, it goes to the game over screen but in flash it generates an infinite loop until I close the application.

Here's the bit that loops.

TypeError: Error #1009: Cannot access a property or method of a null object reference.
	at game_fla::MainTimeline/moveBall()
TypeError: Error #1009: Cannot access a property or method of a null object reference.
	at game_fla::MainTimeline/moveStar()
TypeError: Error #1009: Cannot access a property or method of a null object reference.
	at game_fla::MainTimeline/moveMan()
TypeError: Error #1009: Cannot access a property or method of a null object reference.
	at game_fla::MainTimeline/circleHits()

Thanks.