Concept question. Can you think of a reason why

I have an XML site that has 6 pages. All SWFs loaded into a main swf. On one of the pages I put a music player. Works great. Problem is, when I leave that page and go to another one, the music continues to play. Its like the SWF does not get unloaded completely. If I try to go back to that page, another instance is created and 2 songs are now playing!

Why is this happening? How would I ensure it gets unloaded whenever a new one is loaded?

Thanks.
Rich