First of all sorry for my wrongly placed answer. It was for a different thread.

The point is that the problem could be that it is an AS2 movie. I have found that AS2 movies containing components screw up when loaded into an AS3 movie. I don't know your movie contains components, however I would not be surprised if something else could also screw up the movie.
As far as I know movies only stay in cache memory of the browser. So the problem may be that the loaded movie has done something to your parent movie, which remains.