Noob AS3 Button question.

Hey, I have two buttons and here is my code:

import flash.events.MouseEvent;

stop();

B1.addEventListener(MouseEvent.CLICK, onB1Click);

B2.addEventListener(MouseEvent.CLICK, onB2Click);

//this will give you the hand cursor on rollover:

//now to handle the incoming click events

function onB1Click(e:MouseEvent):void

{ 

    if (this.currentFrame < this.totalFrames)

    {

        this.gotoAndStop(this.currentFrame + 1);

        trace('B1 Clicked: moved to next frame (' + this.currentFrame + ')\n');

    }

    else

    {

        trace('B1 Clicked: you are on the last frame already.\n');

    }

}

function onB2Click(e:MouseEvent):void

{  

    if (this.currentFrame > 1)

    {

        this.gotoAndStop(this.currentFrame - 1);

        trace('B2 Clicked: moved to previous frame (' + this.currentFrame + ')\n');

    }

    else

    {

        trace('B2 Clicked: you are on the first frame already.\n');

    }

}

Can Somebody tell me why this isn't working?

If anyones interested, here is a link to my flash file:
http://uploading.com/files/968cee24/Photo%2Bgallery%2B2.fla/

Thanks.