Button inside movie clip

I'm having a problem getting a button to work. I have a movie clip, which has several layers inside it. When you roll over the movie clip, actionscript makes it play and "open." It stops in the middle to reveal a button. The button is keyframed into one of the layers inside the movie clip. My problem is that you can't press that button! Even though the button is the top layer, it can't be clicked. Why not? How can I make this button usable?

In simpler terms, I have a piano lid movie clip, the lid opens when you roll over it, revealing a key underneath. But You can't press the key. Why not?

You should be able to click on the button even if it has got another mc over the top of it. The only way to stop you clickong on it would be to have another button on top of that button... makin sence?

But I doubt thats the case. Can you post the fla file?

XFM

The FLA:
http://www.delvarworld.com/stuff/nav4.fla

If you go to the second frame of the main stage and click on the music button, you see it has rollover and rollout attributes in the actionscript. If you double click on it, you'll see a layer called "gobutton" with a keyframe on it. That keyframe holds the button I want you to be able to click, which is that black circle. But that button can't be touched. Help?

zip the file up to your server the browser is trying to display the fla but cant

Fixed, anyway