Audio Synchronization Problem

When I make animations in flash and put it to music, it sync’s very well when i play it and test it in the .fla. But once i play it through the .swf or publish it and play through the .html, the sync is all off. The music sounds the same; I think the fps is just lowering causing the sync to go off.

 Is there any way i can get around this problem to have properly synced animations? Any help would be great. Thanks!