Problem with drag and drop

Hi! I'm having a problem with getting this code working, basically I want to drag and drop two things onto another the things dissapear then it moves onto a new page, the first item works properly but then the second item wont dissapear and remains stuck to the cursor. Heres the code I'd be greatful of any help.

import flash.events.MouseEvent;

import fl.motion.MotionEvent;

stop();

Back6_btn.addEventListener(MouseEvent.CLICK, onBack6Click)

function onBack6Click(event:MouseEvent):void{

    gotoAndPlay("Bedroom2");

}

    Forward6_btn.addEventListener(MouseEvent.CLICK, onForward6Click)

function onForward6Click(event:MouseEvent):void{

    gotoAndPlay('Brother bit');

}

var inGran:Number=0;

Gin.addEventListener(MouseEvent.MOUSE_DOWN, dragOn);

Tonic.addEventListener(MouseEvent.MOUSE_DOWN, dragOn);

function dragOn(event:MouseEvent):void {

    event.target.startDrag(false);

}

{

    stage.addEventListener(MouseEvent.MOUSE_UP, dragOff);

    }

function dragOff(event:MouseEvent):void {

    event.target.stopDrag();

    if (event.target.dropTarget!=null&&event.target.dropTarget.parent==Gran) {

        event.target.visible=false;

        inGran++;

    }

    stage.removeEventListener(MouseEvent.MOUSE_UP, dragOff);

}

function checkPage(e:Event):void {

    if (inGran==2) {

        gotoAndPlay("Bedroom1");

    }

}