Do you have after effects?

If not, have you tried importing QT movie into Premiere, and then importing the original wav file in Premiere? not the wav exported from Flash. Then you can edit the sound back up. As far as why Flash doesn't export the sound in movie clips with an avi or mov, im not sure why. Perhaps someone else here will know. Thats why I just import the swf into After Effects and that works for me.