FLV Problems (no sound)

Because my flash project is more like a movie, I originally converted the .FLA to a .MOV, but then found out I had to switch it back to a .FLV. However when I convert the .MOV to .FLV, I can’t get the sound to work. In the encoding section it says that the sound is being encoded in mp3 format, but oddly I cannot change those settings, which in the end doesnt matter since sound doesn’t work at all. Has anyone had this same problem or have any solution for it? I’d be most grateful for the help, thanks!