choose your own adventure: mystery issue

[pbars319]

Situation:

I'm trying to basically make a "choose your own adventure" type of animation, which is going to explain various parts of a painting.

First there is a stopped frame with a play button on it.
That button plays an animated introduction (if you want to skip the intro, you simply click anywhere on the screen and it'll bring you to the menu).
You end up at a menu with various options to go to.

I got the first and second part to work, now I am designing the menu. Before I do that I wanted to test if my "restart" button worked (a button that brings you to frame one again).
it does bring you back to frame 1; HOWEVER, the play button no longer works...??? there are no compiler errors or output messages.

Here is my script for the first frame (frames 1-9 actually):

import flash.events.MouseEvent;
import flash.media.SoundMixer;

SoundMixer.stopAll()

function introBtnClick(evt:Event):void{
    gotoAndPlay("intro");
}

introBtn1.addEventListener(MouseEvent.CLICK, introBtnClick); 

Here is my script for the animated intro (frames 10-19). The first frame has a movieclip nested into it:

import flash.events.MouseEvent;
import flash.media.SoundMixer;

function menuBtn1Click(evt:Event):void{
    gotoAndPlay("menu")
    SoundMixer.stopAll();
}

menuBtn1.addEventListener(MouseEvent.CLICK, menuBtn1Click); 

And here's my script for the menu section:

import flash.events.MouseEvent;

function restartBtnClick(evt:Event):void{
    gotoAndPlay("restart")
}

restartBtn.addEventListener(MouseEvent.CLICK, restartBtnClick); 

note: funny thing is, the script for the play intro button and the invisible skip into button are the same, simply with different labels and instance names. If I direct the restart button to the intro animation, it works fine (and the invisible "skip intro" button works as well). What the deal!!!???