This is the entire InGameScript code

Code:
StartButton.addEventListener(MouseEvent.CLICK, StartGame);
//ContinueButton.addEventListener(MouseEvent.CLICK, ContinueGame);

function StartGame(event:MouseEvent):void

{

var ChosenCards:Array = [AlfaPlay, AscariPlay, AstonOnePlay, AstonRapPlay, AudiPlay, BEngineeringPlay, BentleyPlay, BertonePlay, BristolPlay, BugattiPlay, ChevroletPlay, ChryslerPlay, DauerPlay, DevonPlay, DodgePlay, Ferrari458Play, FerrariEnzPlay, FiskerPlay, FordPlay, GilletPlay, GTAPlay, GumpertApoPlay, GumpertTorPlay, HennesseyPlay, JaguarXJ2Play, JaguarXKRPlay, JossPlay, KeplerPlay, KoenigseggAgePlay, KoenigseggCCXPlay, LamborghiniAvePlay, LamborghiniMurPlay, LanciaPlay, LexusPlay, LotecPlay, LotusPlay, MaseratiGraPlay, MaseratiMC1Play, McLarenF1Play, McLarenMP4Play, MercedesPlay, MoslerPlay, NissanPlay, NoblePlay, PaganiHuaPlay, PaganiZonPlay, Porsche918Play, PorscheCarPlay, RossionPlay, SaleenS5SPlay, SaleenS7Play, SpykerPlay, SSCPlay, SVSPlay, TeslaPlay, TVRPlay, UltimaPlay, VectorAvtPlay, WiesmannPlay, ZenvoPlay];

var b:Array = ChosenCards.sort(CardShuffle); //Setting up an array to shuffle cards
	
	function CardShuffle(ChosenCards,b):Number {
		
		var num : Number = Math.round(Math.random()*2)-1;
	
		return num;
	}

var PlayerCards:Array = []; //Sets up an array to hold the players cards.

var AICards:Array = []; //Same as above but for the ai's cards
	
for (var p:int = 0; p <60; p++) { //Select 30 of the cards available.
	
	var TargetHand:Array; //An array containing all cards.
	
	if (p % 2 == 0){ //Gives half of the cards to the player.
		
		TargetHand = PlayerCards;
		
		}else{ //and then give the other half to the ai.
			
		TargetHand = AICards;
		
	}
	
	TargetHand.push(ChosenCards[p]);
	
	}

ContinueButton.visible = false;

	trace("Players 30 random cards\n");
	for(var s:int = 0; s < PlayerCards.length; s++)
	{
		trace((s + 1) + ". " + PlayerCards[s].name)
		//Problem could be from this piece of code.
	}
	
	trace("\nAI 30 random cards\n");
	for(var t:int = 0; t < AICards.length; t++)
	{
		trace((t + 1) + ". " + AICards[t].name)
		
	}
	
	function PickRandomCard(max:int):Number
	{
		
		var pick:Number = new Number(Math.round(Math.random() * max));
		
		return(pick);
		
	}

	var PickedPlayerCard:String = new String();
	var PickedAICard:String = new String();
	
	PickedPlayerCard = PlayerCards[PickRandomCard(15)].name;
	PickedAICard = AICards[PickRandomCard(15)].name;
	
	trace("\nPlayer First Card: " + PickedPlayerCard);
	trace("AI First Card: " + PickedAICard);
	
	this[PickedPlayerCard].visible = true; //Making chosen card visible.
	this[PickedPlayerCard].x = 75; //Positioning chosen card.
	this[PickedAICard].visible = true;
	this[PickedAICard].x = 430;
	
	StartButton.visible = false;
	BackButton.visible = false;
	
	SpeedButton.x = 99; //Setting position of card buttons so player can choose a value.
	ZerotoSixtyButton.x = 99;
	PowerButton.x = 99;
	WeightButton.x = 99;
	CostButton.x = 99;
	
	SpeedButton.buttonMode = true;
	ZerotoSixtyButton.buttonMode = true;
	PowerButton.buttonMode = true;
	WeightButton.buttonMode = true;
	CostButton.buttonMode = true;
	
	SpeedButton.visible = true;
	ZerotoSixtyButton.visible = true;
	PowerButton.visible = true;
	WeightButton.visible = true;
	CostButton.visible = true;
	
	SpeedButton.addEventListener(MouseEvent.CLICK, SelectSpeed); //Waits for chosen buttons to be pressed.
	ZerotoSixtyButton.addEventListener(MouseEvent.CLICK, SelectZerotoSixty);
	PowerButton.addEventListener(MouseEvent.CLICK, SelectPower);
	WeightButton.addEventListener(MouseEvent.CLICK, SelectWeight);
	CostButton.addEventListener(MouseEvent.CLICK, SelectCost);
	
	function SelectSpeed(event:MouseEvent):void //If this button is clicked.

	{
		if(this[PickedPlayerCard].visible){ //Checks if this is visible.
			
			if(this[PickedPlayerCard].Speed > this[PickedAICard].Speed) //Is this chosen value is larger and all of above is true ...
			
			{
				
				PlayerWinner.visible = true; //Do this.
				AILoser.visible = true;
		
				} else if (this[PickedPlayerCard].Speed < this[PickedAICard].Speed){ //If not and this is true do this.
			
				PlayerLoser.visible = true;
				AIWinner.visible = true;
				
				} else { //Else if neither are true do this.
					
				PlayerDraw.visible = true;
				AIDraw.visible = true;
				
			}
		}
	}
	
	function SelectZerotoSixty(event:MouseEvent):void

	{
		if(this[PickedPlayerCard].visible){
			
			if(this[PickedPlayerCard].ZerotoSixty < this[PickedAICard].ZerotoSixty) //Notice that this statement is the same as above except we're now asking if this this chosen value is smaller instead of larger.
			
			{
				
				PlayerWinner.visible = true;
				AILoser.visible = true;
		
				} else if (this[PickedPlayerCard].ZerotoSixty > this[PickedAICard].ZerotoSixty){
				PlayerLoser.visible = true;
				AIWinner.visible = true;
				
				} else {
					
				PlayerDraw.visible = true;
				AIDraw.visible = true;
				
			}
		}
	}
	
	function SelectPower(event:MouseEvent):void

	{
		if(this[PickedPlayerCard].visible){
			
			if(this[PickedPlayerCard].Power > this[PickedAICard].Power)
			
			{
				
				PlayerWinner.visible = true;
				AILoser.visible = true;
		
				} else if (this[PickedPlayerCard].Power < this[PickedAICard].Power){
			
				PlayerLoser.visible = true;
				AIWinner.visible = true;
				
				} else {
					
				PlayerDraw.visible = true;
				AIDraw.visible = true;
				
			}
		}
	}
	
	function SelectWeight(event:MouseEvent):void

	{
		if(this[PickedPlayerCard].visible){
			
			if(this[PickedPlayerCard].Weight < this[PickedAICard].Weight)
			
			{
				
				PlayerWinner.visible = true;
				AILoser.visible = true;
		
				} else if (this[PickedPlayerCard].Weight > this[PickedAICard].Weight){
				PlayerLoser.visible = true;
				AIWinner.visible = true;
				
				} else {
					
				PlayerDraw.visible = true;
				AIDraw.visible = true;
				
			}
		}
	}
	
	function SelectCost(event:MouseEvent):void

	{
		if(this[PickedPlayerCard].visible){
			
			if(this[PickedPlayerCard].Cost > this[PickedAICard].Cost)
			
			{
				
				PlayerWinner.visible = true;
				AILoser.visible = true;
		
				} else if (this[PickedPlayerCard].Cost < this[PickedAICard].Cost){
			
				PlayerLoser.visible = true;
				AIWinner.visible = true;
				
				} else {
					
				PlayerDraw.visible = true;
				AIDraw.visible = true;
				
			}
		}
	}
	
	setChildIndex(SpeedButton,numChildren - 1); //Sets this button to the front of the scene.
	setChildIndex(ZerotoSixtyButton,numChildren - 1);
	setChildIndex(PowerButton,numChildren - 1);
	setChildIndex(WeightButton,numChildren - 1);
	setChildIndex(CostButton,numChildren - 1);
	
}
The code works fine and the start button makes the first 2 cards appear until I click the value selection button (either SpeedButton or so on) and then he code gives this error: TypeError: Error #1010: A term is undefined and has no properties.
at Function/<anonymous>()