TypeError: Error #1009: Variable

So I make a as3 timeline. And this hapen

TypeError: Error #1009: Cannot access a property or method of a null object reference.

    at arrow_Scene1_fla::MainTimeline/frame2()

The code at frame 2 is

stop();

var myscore = 0;

score.text = "$" + myscore;

var mylive = 3;

live.text = "Live:" + mylive;

var myspin = 0;

spin.text = "Spin:" + myspin;

btn_play.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndPlayFromFrame);

function fl_ClickToGoToAndPlayFromFrame(event:MouseEvent):void

{

    gotoAndPlay(5);

}

btn_rule.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndPlayFromFrame_2);

function fl_ClickToGoToAndPlayFromFrame_2(event:MouseEvent):void

{

    gotoAndPlay(3);

}

btn_credit.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndPlayFromFrame_3);

function fl_ClickToGoToAndPlayFromFrame_3(event:MouseEvent):void

{

    gotoAndPlay(4);

}

The bolded one is I suspect the cause.

Here's a thing

a) No matter what, when I'm making a variable for score. That message appear. Even a new file. ONLY

RARE CASE WHEN THAT MATTER DOESN'T MATTER.

Old file not affected, but new file does.

b) The bolded syntax, no matter where I move it, the error follows. The old frame err message gone