Error when debugging Flash Game - actionscript-3

Question

I keep on getting this error
TypeError: Error #1010: A term is undefined and has no properties.
at GameController/update()[C:\Users\Administrator\Desktop\Better PW\GameController.as:32]
I have the terms defined, yet it keeps giving me an error. Please Help Debug! TY.
package
{
import flash.display.*;
import flash.events.*;
import flash.ui.*;
import flash.display.MovieClip;
import flash.events.*;
import flash.geom.*;
import flash.text.*;
public class GameController extends MovieClip
{
private var score1, score2, year, delay, p1, p2:Number;
private var phase, game_winner:String;
private var playDone:Boolean;
public function GameController()
{}
private function update(evt:Event){
if(p1 == 1 && p2 == 1){
score1= score1+1;
score2= score2+1;
}else if(p1 == 1 && p2 == 2){
score1= score1+3
}else if (p2 == 1 && p1 == 2){
score2= score2+3
}else if (p1 == 2 && p2 == 2){
score1= score1+2
score2= score2+2
}
txtPlayerUno.text = score1.toString();
txtPlayerDous.text = score2.toString();
p1 = 0
p2 = 0
}
private function playerRound(){
}
public function startmenu()
{
stop();
btnStartGame.addEventListener(MouseEvent.CLICK, gotoStartGame);
btnHowToPlay.addEventListener(MouseEvent.CLICK, gotohowtoplay);
}
private function gotoStartGame(evt:MouseEvent)
{
btnStartGame.removeEventListener(MouseEvent.CLICK, gotoStartGame);
btnHowToPlay.removeEventListener(MouseEvent.CLICK, gotohowtoplay);
gotoAndStop("game");
}
public function starthowtoplay()
{
btnBack.addEventListener(MouseEvent.CLICK, gotoMenu);
}
private function gotohowtoplay(evt:MouseEvent)
{
btnStartGame.removeEventListener(MouseEvent.CLICK, gotoStartGame);
btnHowToPlay.removeEventListener(MouseEvent.CLICK, gotohowtoplay);
gotoAndStop("howtoplay");
}
public function startgame() :void
{
addEventListener(Event.ADDED_TO_STAGE, gameAddedToStage );
mcGameStage.addEventListener(Event.ENTER_FRAME,update);
}
private function gotoMenu(evt:MouseEvent)
{
btnBack.removeEventListener(MouseEvent.CLICK, gotoMenu);
gotoAndStop("menu");
}
private function keyDownHandler(evt:KeyboardEvent):void
{
//1- War 2-Peace
if (evt.keyCode == 37)
{
p1= 2
}
else if (evt.keyCode == 39)
{
p1= 1
}
if (evt.keyCode == 65)
{
p2=2
}
else if (evt.keyCode == 68)
{}
}
private function gameAddedToStage(evt: Event):void
{
stage.addEventListener(KeyboardEvent.KEY_DOWN,keyDownHandler);
}
}
}