I wish I knew how to fix this for you.
There was a book called flash hacks from oreilly.
In it they said exporting your framedata/sound to a new .fla might help with bugs or errors, because of things like undo history.
If this doesnt help, Im not sure what to do. Sorry bud, goodluck.
blazelauncherer
Try exporting your toon as a png sequence and putting it in an editing software, that'll probably work. oh yea don't forget to put your sound file in there too.