Stop and Play button doesn't work

Content
1

Hallo!

I have the following problem. I am trying to insert a stop and play button into a flash animation but it doesn’t work.
The movie clip with its changing images works but there are no buttons although I have put them on a seperate layer in the same timeframe.

I would be very happy if anybody could help me.

2

What Actionscript have you got for each button?

3

1st layer: movieclip
2nd layer: play button with instance name: play_btn
3rd layer: stop button with instance name: stop_btn
4th layer 1st frame: play_btn.onRelease = function(){
_root.play();
};
stop_btn.onRelease = function(){
_root.stop();
};