Problem to start them and get them in sync

I have one movieclip (a black square) in the main timeline . In that movieclip i have a small square (purple) that is moving around in the black square. The movieclip is 60 frames long and have stop action in the last frame. the main timeline is also 60 frames long and have a stop action in the last frame. In the main timeline the black square is moving. i have a button that i use to start the process. So when i see the movie , the black square is moving and the little purple square is moving inside the black square and then stop. everything is fine so far. but when i press the button to play it again everything is out of order. 'Not the black square but the litlle purple square is not following like it did the first time.

thanks in advance