Count Collisions Problem in Shooting Game

Question

Hi,  I am working a simple game in which a ship fires at approaching asteroids and I am having problems with the collision between the ship and the
asteroid. In the ship movieClipI have made it glow red from frame 6 to signify the first 3 collisions and loss of life and then then for the fourth collision I
have made a alpha tween from frame 87 inside the ship so that it disappears to signify end of game. I have used a counter as shown below but all the ship
does is glow so never gets to frame 87. Thanks for taking time to view this.
//import some important flash libraries.
import flash.events.KeyboardEvent;
import flash.events.Event;
import flash.display.MovieClip;
import flash.display.Sprite;
var countCollisions:Number =0 ;
var astArray:Array = new Array();
var speed:Number = 10;
//initializes variables.
var key_left:Boolean = false;
var key_right:Boolean = false;
var key_up:Boolean = false;
var key_down:Boolean = false;
var key_space:Boolean = false;
var shootLimiter:Number=0;
//Checks if the player presses a key.
var timer:Timer = new Timer(2000, 10);
timer.addEventListener(TimerEvent.TIMER, AddAsteroid);
timer.start();
stage.addEventListener(KeyboardEvent.KEY_DOWN,KeyDown);
stage.addEventListener(KeyboardEvent.KEY_UP,KeyUp);
var ship:MovieClip = new Ship()
var backgr:MovieClip = new Background();
backgr.x = 0;
backgr.y = 45;
addChild(backgr);
addChild(ship);
function AddAsteroid(e:TimerEvent):void
var asteroid:MovieClip = new Asteroid();   
asteroid.x = 800;
asteroid.y = Math.round(Math.random()*700);
astArray.push(asteroid);  
addChild(asteroid);
asteroid.addEventListener(Event.ENTER_FRAME,asteroidmove);   
function asteroidmove(e:Event):void
asteroid.x--
for(var i=0; i<astArray.length; i++)
  if(astArray[i].hitTestObject(ship))
  countCollisions++;
  ship.gotoAndPlay(6);
   if(countCollisions ==4)
   ship.gotoAndPlay(87);
  if(astArray[i].stage)
        removeChild(astArray[i]);
        removeEventListener(Event.ENTER_FRAME,asteroidmove);
addEventListener(Event.ENTER_FRAME,backgroundmove);
function backgroundmove(e:Event):void
backgr.x -= 1;
if(backgr.x < -2110)
backgr.x = 0;
//Lets the function main play every frame.
addEventListener(Event.ENTER_FRAME,Main);
//create the function main.
function Main(event:Event){
CheckKeys();
//create the function KeyDown.
function KeyDown(event:KeyboardEvent){
if(event.keyCode == 37){  //checks if left arrowkey is pressed.
  key_left = true;
if(event.keyCode == 39){  //checks if right arrowkey is pressed.
  key_right = true;
if(event.keyCode == 38){  //checks if up arrowkey is pressed.
  key_up = true;
if(event.keyCode == 40){  //checks if down arrowkey is pressed.
  key_down = true;
if(event.keyCode == 32){  //checks if down arrowkey is pressed.
  key_space = true;
function KeyUp(event:KeyboardEvent){
if(event.keyCode == 37){  //checks if left arrowkey is released.
  key_left = false;
if(event.keyCode == 39){  //checks if right arrowkey is released.
  key_right = false;
if(event.keyCode == 38){  //checks if up arrowkey is released.
  key_up = false;
if(event.keyCode == 40){  //checks if down arrowkey is released.
  key_down = false;
if(event.keyCode == 32){  //checks if down arrowkey is released.
  key_space = false;
function CheckKeys()
shootLimiter += 1;
if(key_left)
  setDirection(1);
  ship.x -= 5;
if(key_right)
  setDirection(0);
  ship.x += 5;
if(key_up){
  ship.y -= 5;
if(key_down){
  ship.y += 5;
if((key_space) && (shootLimiter > 8))
shootLimiter = 0;
var b = new Bullet();
addChild(b);
b.x = ship.x + 50;
b.y = ship.y + 3;
addEventListener(Event.ENTER_FRAME,moveBullet);
function moveBullet(e:Event):void
b.x +=10;
  if(b.x > 600)
   if(contains(b))
   removeChild(b);
          removeEventListener(Event.ENTER_FRAME,moveBullet);
for(var i=0; i<astArray.length; i++)
  if(astArray[i].hitTestObject(b))
  removeChild(b);
  removeChild(astArray[i]);
  removeEventListener(Event.ENTER_FRAME,moveBullet);
function setDirection(param) {
if (param == 0) {
  ship.scaleX = 1;
} else {
  ship.scaleX = -1;

Answer 1

Thanks for your comments. I have amended the code but get the following error and the ship goes to frame 87 on the second collision.
Can you tell me if I am on the right lines ?
The supplied DisplayObject must be a child of the caller.
at flash.display::DisplayObjectContainer/removeChild()
at Function/<anonymous>()
for(var i=0; i<astArray.length; i++)
  if(astArray[i].hitTestObject(ship))
  countCollisions++;
  removeChild(astArray[i]);
   if(countCollisions >= 4)
   ship.gotoAndPlay(87);
   removeEventListener(Event.ENTER_FRAME,asteroidmove);
   else
   ship.gotoAndPlay(6);
  //if(astArray[i].stage)
        //removeChild(astArray[i]);
  //MovieClip(astArray[i]).removeEventListener(Event.ENTER_FRAME, asteroidmove);
        //removeEventListener(Event.ENTER_FRAME,asteroidmove);