movieClip stopped playing by itself

Hi all,

I encountered this weird problem that my movieclip stopped playing at
a certain frame by itself. I have a movieclip with as3 code in it, and it will
have animation when you rollover. I put this movieclip in another movieclip.
I was working fine, however after I added some other things, it just stopped
working. Another weird part is that I put it in four movieclips and it will work in
the first one but not the others. It will just stop at a certain frame no matter
if I write something in that movieclip or I write something outside of it to tell
it to play… Anyone has this kind of problem before? Thanks.

-christine