Undefined Symbol Somewhere

/*
getting this Stack Trace:
TypeError: Error #1010: A term is undefined and has no properties.
    at WheelWithWheels_fla::MainTimeline/loadLetterBoard()[WheelWithWheels_fla.MainTimeline::frame62:103]
    at WheelWithWheels_fla::MainTimeline/frame62()[WheelWithWheels_fla.MainTimeline::frame62:10]
    at flash.display::MovieClip/gotoAndPlay()
    at WheelWithWheels_fla::MainTimeline/onePlayerGame()[WheelWithWheels_fla.MainTimeline::frame61:9]

I have all this code in Frame 60*/
import flash.events.KeyboardEvent;
import flash.display.MovieClip;

var numTurns:Number = 7;
var score:Number = 0;

var spinKey:uint = 32; //space
var buyKey:uint = 66;//b

loadLetterBoard();
function loadLetterBoard() {

    var topRow:Array = new Array();
    var middleFirst:Array = new Array();
    var middleSecond:Array = new Array();
    var bottomRow:Array = new Array();

    for(var i:int=0;i<=13;i++){
        var new_mc = new MovieClip();
        addChild(new_mc);
        topRow.push(new_mc);
    };
    topRow[0].mask = unused_mc;
    topRow[0].x = 433.0;
    topRow[0].y = 55.0;
    topRow[0].width = 94.0;
    topRow[0].height = 140.1;
    topRow[1].mask = unused_mc;
    topRow[1].x = 521.0;
    topRow[1].y = 55.0;
    topRow[1].width = 94.0;
    topRow[1].height = 140.1;
    topRow[2].mask = unused_mc;
    topRow[2].x = 613.0;
    topRow[2].y = 55.0;
    topRow[2].width = 94.0;
    topRow[2].height = 140.1;
    topRow[3].mask = unused_mc;
    topRow[3].x = 703.0;
    topRow[3].y = 55.0;
    topRow[3].width = 94.0;
    topRow[3].height = 140.1;
    topRow[4].mask = unused_mc;
    topRow[4].x = 793.0;
    topRow[4].y = 55.0;
    topRow[4].width = 94.0;
    topRow[4].height = 140.1;
    topRow[5].mask = unused_mc;
    topRow[5].x = 521.0;
    topRow[5].y = 55.0;
    topRow[5].width = 94.0;
    topRow[5].height = 140.1;
    topRow[6].mask = unused_mc;
    topRow[6].x = 973.0;
    topRow[6].y = 55.0;
    topRow[6].width = 94.0;
    topRow[6].height = 140.1;
    topRow[7].mask = unused_mc;
    topRow[7].x = 1063.0;
    topRow[7].y = 55.0;
    topRow[7].width = 94.0;
    topRow[7].height = 140.1;
    topRow[8].mask = unused_mc;
    topRow[8].x = 1153.0;
    topRow[8].y = 55.0;
    topRow[8].width = 94.0;
    topRow[8].height = 140.1;
    topRow[9].mask = unused_mc;
    topRow[9].x = 1243.0;
    topRow[9].y = 55.0;
    topRow[9].width = 94.0;
    topRow[9].height = 140.1;
    topRow[10].mask = unused_mc;
    topRow[10].x = 1333.0;
    topRow[10].y = 55.0;
    topRow[10].width = 94.0;
    topRow[10].height = 140.1;
    topRow[11].mask = unused_mc;
    topRow[11].x = 1423.0;
    topRow[11].y = 55.0;
    topRow[11].width = 94.0;
    topRow[11].height = 140.1;
    topRow[12].mask = unused_mc;
    topRow[12].x = 1513.0;
    topRow[12].y = 55.0;
    topRow[12].width = 94.0;
    topRow[12].height = 140.1

    for (var j:int = 0; i <= 15;i++){
        addChild(new_mc);
        middleFirst.push(new_mc);
    };
    middleFirst[0].mask = unused_mc;
    middleFirst[0].x = 333.0;
    middleFirst[0].y = 202.0;
    middleFirst[0].width = 94.0;
    middleFirst[0].height = 140.1;
    middleFirst[1].mask = unused_mc;
    middleFirst[1].x = 433.0;
    middleFirst[1].y = 202.0;
    middleFirst[1].width = 94.0;
    middleFirst[1].height = 140.1;
    middleFirst[2].mask = unused_mc;
    middleFirst[2].x = 523.0;
    middleFirst[2].y = 202.0;
    middleFirst[2].width = 94.0;
    middleFirst[2].height = 140.1;
    middleFirst[3].mask = unused_mc;
    middleFirst[3].x = 613;
    middleFirst[3].y = 202.0;
    middleFirst[3].width = 94.0;
    middleFirst[3].height = 140.1;
    middleFirst[4].mask = unused_mc;
    middleFirst[4].x = 703.0;
    middleFirst[4].y = 202.0;
    middleFirst[4].width = 94.0;
    middleFirst[4].height = 140.1;
    middleFirst[5].mask = unused_mc;
    middleFirst[5].x = 793.0;
    middleFirst[5].y = 202.0;
    middleFirst[5].width = 94.0;
    middleFirst[5].height = 140.1;
    middleFirst[6].mask = unused_mc;
    middleFirst[6].x = 883.0;
    middleFirst[6].y = 202.0;
    middleFirst[6].width = 94.0;
    middleFirst[6].height = 140.1;
    middleFirst[7].mask = unused_mc;
    middleFirst[7].x = 973.0;
    middleFirst[7].y = 202.0;
    middleFirst[7].width = 94.0;
    middleFirst[7].height = 140.1;
    middleFirst[8].mask = unused_mc;
    middleFirst[8].x = 1063.0;
    middleFirst[8].y = 202.0;
    middleFirst[8].width = 94.0;
    middleFirst[8].height = 140.1;
    middleFirst[9].mask = unused_mc;
    middleFirst[9].x = 1153.0;
    middleFirst[9].y = 202.0;
    middleFirst[9].width = 94.0;
    middleFirst[9].height = 140.1;
    middleFirst[10].mask = unused_mc;
    middleFirst[10].x = 1243.0;
    middleFirst[10].y = 202.0;
    middleFirst[10].width = 94.0;
    middleFirst[10].height = 140.1;
    middleFirst[11].mask = unused_mc;
    middleFirst[11].x = 1333.0;
    middleFirst[11].y = 202.0;
    middleFirst[11].width = 94.0;
    middleFirst[11].height = 140.1;
    middleFirst[12].mask = unused_mc;
    middleFirst[12].x = 1423.0;
    middleFirst[12].y = 202.0;
    middleFirst[12].width = 94.0;
    middleFirst[12].height = 140.1;
    middleFirst[13].mask = unused_mc;
    middleFirst[13].x = 1513.0;
    middleFirst[13].y = 202.0;
    middleFirst[13].width = 94.0;
    middleFirst[13].height = 140.1;
    middleFirst[14].mask = unused_mc;
    middleFirst[14].x = 1603.0;
    middleFirst[14].y = 202.0;
    middleFirst[14].width = 94.0;
    middleFirst[14].height = 140.1;
    middleFirst[15].mask = unused_mc;
    middleFirst[15].x = 1701.0;
    middleFirst[15].y = 202.0;
    middleFirst[15].width = 94.0;
    middleFirst[15].height = 140.1;
    /*
    for (var i:int = 0; i <= 15;i++){
        addChild(new_mc);
        middleFirst.push(new_mc);
    }
    middleFirst[0].x = 333.0;
    middleFirst[1].x = 433.0;
    middleFirst[2].x = 523.0;
    middleFirst[3].x = 613;
    middleFirst[4].x = 703.0;
    middleFirst[5].x = 793.0;
    middleFirst[6].x = 883.0;
    middleFirst[7].x = 973.0;
    middleFirst[8].x = 1063.0;
    middleFirst[9].x = 1153.0;
    middleFirst[10].x = 1243.0;
    middleFirst[11].x = 1333.0;
    middleFirst[12].x = 1423.0;
    middleFirst[13].x = 1513.0;
    middleFirst[14].x = 1603.0;
    middleFirst[15].x = 1701.0;
    */
}//end loadLetterboard


this.txt_Turns.text = "Turns: " + numTurns.toString();
this.txt_Score.text = "$" + score;

stage.addEventListener(KeyboardEvent.KEY_DOWN,keyDownListener);

function keyDownListener(e:KeyboardEvent):void {
    if (e.keyCode == Keyboard.ENTER) {
        //gotoAndPlay("SinglePlayerSolve")
    }else if (e.keyCode == Keyboard.SPACE) {
        //spin();
        //gotoAndPlay("Spin")
    }else if (e.keyCode == buyKey){
        //buyVowel();
        //gotoAndPlay("BuyVowel");
    }

}//end keyDownListener

//Comment stop() out later just use for a Test
stop();

I have no clue what else is wrong any help would be great