Bug Issues Conflict with in code

Okay i am creating a variable mySound_sound and loading an mp3 into it. This works fine, then i assign some functions to two buttons to stop and play this file on press. Then this two are placed in a movie clip and placed in the movie.

Then i have a mediaPlayback component in the there also. However when i click play on the sound it mutes the movie any ideas how i can prevent this from happening?

Thanks