Error #2007: Parameter listener must be non-null

Hi I’m creating a winnie the pooh colouring in game and I’m getting
TypeError: Error #2007: Parameter listener must be non-null.
at flash.events::EventDispatcher/addEventListener()
at ColouringinGame_fla::MainTimeline/frame1()

The Code on the main time line is

import flash.events.MouseEvent;

var myColor = 0xFFFFFF;

function getBlack(event:MouseEvent):void {
myColor = 0x000000;
}
function getLightBlue(event:MouseEvent):void {
myColor = 0x33CCFF;
}
function getDarkBlue(event:MouseEvent):void {
myColor = 0x3300CC;
}
function getGrey(event:MouseEvent):void {
myColor = 0x666666;
}
function getLightGreen(event:MouseEvent):void {
myColor = 0x66CC66;
}
function getDarkGreen(event:MouseEvent):void {
myColor = 0x003300;
}
function getBrown(event:MouseEvent):void {
myColor = 0x663300;
}
function getOrange(event:MouseEvent):void {
myColor = 0xFF9900;
}
function getPink(event:MouseEvent):void {
myColor = 0xFF66FF;
}
function getSkin(event:MouseEvent):void {
myColor = 0xFFCCCC;
}
function getPurple(event:MouseEvent):void {
myColor = 0x6600CC;
}
function getRed(event:MouseEvent):void {
myColor = 0xFF0000;
}
function getWhite(event:MouseEvent):void {
myColor = 0xFFFFFF;
}
function getYellow(event:MouseEvent):void {
myColor = 0xFFFF00;
}

this.b_black.addEventListener(MouseEvent.MOUSE_DOWN, getBlack);
this.b_grey.addEventListener(MouseEvent.MOUSE_DOWN, getGrey);
this.b_dgreen.addEventListener(MouseEvent.MOUSE_DOWN, getDarkGreen);
this.b_lblue.addEventListener(MouseEvent.MOUSE_DOWN, getLightBlue);
this.b_dblue.addEventListener(MouseEvent.MOUSE_DOWN, getDarkBlue);
this.b_lgreen.addEventListener(MouseEvent.MOUSE_DOWN, getLightGreen);
this.b_brown.addEventListener(MouseEvent.MOUSE_DOWN, getBrown);
this.b_orange.addEventListener(MouseEvent.MOUSE_DOWN, getOrange);
this.b_pink.addEventListener(MouseEvent.MOUSE_DOWN, getPink);
this.b_purple.addEventListener(MouseEvent.MOUSE_DOWN, getPurple);
this.b_red.addEventListener(MouseEvent.MOUSE_DOWN, getRed);
this.b_white.addEventListener(MouseEvent.MOUSE_DOWN, getWhite);
this.b_yellow.addEventListener(MouseEvent.MOUSE_DOWN, getYellow);
this.b_skin.addEventListener(MouseEvent.MOUSE_DOWN, getSkin);

this.b_black.addEventListener(MouseEvent.MOUSE_UP, this.brush.colorMe);
this.b_grey.addEventListener(MouseEvent.MOUSE_UP, this.brush.colorMe);
this.b_dgreen.addEventListener(MouseEvent.MOUSE_UP, this.brush.colorMe);
this.b_lblue.addEventListener(MouseEvent.MOUSE_UP, this.brush.colorMe);
this.b_dblue.addEventListener(MouseEvent.MOUSE_UP, this.brush.colorMe);
this.b_lgreen.addEventListener(MouseEvent.MOUSE_UP, this.brush.colorMe);
this.b_brown.addEventListener(MouseEvent.MOUSE_UP, this.brush.colorMe);
this.b_orange.addEventListener(MouseEvent.MOUSE_UP, this.brush.colorMe);
this.b_pink.addEventListener(MouseEvent.MOUSE_UP, this.brush.colorMe);
this.b_purple.addEventListener(MouseEvent.MOUSE_UP, this.brush.colorMe);
this.b_red.addEventListener(MouseEvent.MOUSE_UP, this.brush.colorMe);
this.b_white.addEventListener(MouseEvent.MOUSE_UP, this.brush.colorMe);
this.b_yellow.addEventListener(MouseEvent.MOUSE_UP, this.brush.colorMe);
this.b_skin.addEventListener(MouseEvent.MOUSE_UP, this.brush.colorMe);

this.Pooh.P_legs.addEventListener(MouseEvent.MOUSE_UP, this.Pooh.P_legs.colorMe);
this.Pooh.P_arms.addEventListener(MouseEvent.MOUSE_UP, this.Pooh.P_arms.colorMe);
this.Pooh.P_shirt.addEventListener(MouseEvent.MOUSE_UP, this.Pooh.P_shirt.colorMe);
this.Pooh.P_body.addEventListener(MouseEvent.MOUSE_UP, this.Pooh.P_body.colorMe);
this.Pooh.P_head.addEventListener(MouseEvent.MOUSE_UP, this.Pooh.P_head.colorMe);
this.Pooh.P_tounge.addEventListener(MouseEvent.MOUSE_UP, this.Pooh.P_tounge.colorMe);
this.Pooh.P_Tjar.addEventListener(MouseEvent.MOUSE_UP, this.Pooh.P_Tjar.colorMe);
this.Pooh.P_bjar.addEventListener(MouseEvent.MOUSE_UP, this.Pooh.P_bjar.colorMe);

function moveBrush (event:Event) : void {
this.brush.startDrag (true);
Mouse.hide();
}

this.addEventListener(Event.ENTER_FRAME, moveBrush);

And the code on the brush is

function paint(obj:Object,myColor:Number):void {
var newColor:ColorTransform = new ColorTransform();
newColor.color = myColor;
obj.transform.colorTransform = newColor;
}

function colorMe(event:MouseEvent):void {
this.paint(this.tip, event.target.root.myColor);
}

mouseEnabled = false;