AS 3 Problem

programming flash
1

In Scene 1 I have a movie clip called “mask.” In this movie clip on the A (actions) layer this AS resides:
parent.gotoAndStop(parent.nextSection);

In Scene 1 on the actions layer this AS resides:
stop();

var nextSection:String;

function onHomeClick(evt:MouseEvent):void {
nextSection = “home”
transition.play();
}
btn_home.addEventListener(MouseEvent.CLICK, onHomeClick);

function onMenuClick(evt:MouseEvent):void {
nextSection = “menu”
transition.play();
}
btn_menu.addEventListener(MouseEvent.CLICK, onMenuClick);

I get the Compiler Errors Window saying:

Location: “mask,” layer A…
Description: 1061: Call to a possibly undefined method gotoAndStop through a reference with static type flash.display:DisplayObjectContainer.
Source: parent.gotoAndStop(parent.nextSection);

Location: “mask,” layer A…
Description: 1119: Access of possibly undefined property nextSection through a reference with static type flash.display:DisplayObjectContainer.
Source: parent.gotoAndStop(parent.nextSection);

Can anyone tell me what is wrong? If you can help me, please speak on a very basic level since I am new o CS 3 and very bad at AS. Thanks!