Working in a sound/voice heavy project right now, we keep updating the sound files in the FLA files all the time and they just keep crashing. When playing the sounds in Flash it gets a high pitch noise and is all scramble.
Select the files in library and choose UPDATE, then Clear ASO Cache and export the file. Irritating bug I know but this seems to get my files to play correctly.
PS: Adobe Flash CS4 with WAV sounds.