AS3 troubles!

I’m very new to Flash and AS3, but I’m getting by after completing Todd Perkins’ training book.
I’ve come across my first obstacle that I’m not able to solve.
I’ve created a simple animation.
Here is the basic skeleton:
Main Timeline:nested movieclip:multiple nested movieclips.
I have a button on the main timeline to control one of the movieclips in the ‘multiple nested movieclips’ branch. The code I have in place is :

stop();
function stopbiomovie(event:MouseEvent):void
{
bio_mov.gotoAndStop(1);
}
function playbiomovie(event:MouseEvent):void
{
bio_mov.gotoAndPlay(1);
}
bio_but.addEventListener(MouseEvent.MOUSE_OVER, stopbiomovie);
bio_but.addEventListener(MouseEvent.MOUSE_OUT, playbiomovie);

where bio_mov is the movieclip I want to control. The first nested movieclip is in a keyframe on frame 1 with just a stop(); code in frame 1. When the movieclip finishes, I have code in place to advance the maintimeline to frame 2 and the movieclip remains, looping on its final frame. Everything runs smoothly … until I add the above code in frame 2. When I add this code and attempt to play the project, the first nested movieclip just skips through, and keeps doing so. No button control. I get the following error messages:

1120: Access of undefined property bio_mov.
1120: Access of undefined property bio_mov.
1120: Access of undefined property bio_but.
1120: Access of undefined property bio_but.

with the following sources respective:

bio_mov.gotoAndStop(1);
bio_mov.gotoAndPlay(1)
bio_but.addEventListener(MouseEvent.MOUSE_OVER, stopbiomovie);
bio_but.addEventListener(MouseEvent.MOUSE_OUT, playbiomovie);

Okay, I hope this is a thorough enough description of the problem and what I’m trying to accomplish. Any help would be great. Thanks.

REALLY new to AS3 so most of this is over my head. If I post two files, one pre-error and one post-error, would you be able to diagnose my problem?

[QUOTE=bjkasten;2377588]REALLY new to AS3 so most of this is over my head. If I post two files, one pre-error and one post-error, would you be able to diagnose my problem?[/QUOTE]

Go ahead and post the fla.