Looping Movie Clip

And thanks in advance for willing to help me…

First the movie clips will continue looping.

Then later I will random generate a number,
this number determine which movie clip should be played.

While this movie clip is playing, the rest of the movie clip is still looping.
After this movie have play finish, it should continue random generate a number
and loop the other movieclip.

Attached would be the file i tried out.
Even it’s working well at first but it stopped looping
at a period of time which made me wonder what went wrong.

Once again, thanks and please help >.<