Sounds odd (no pun intended)
Was the file 21 MB before you tried to embed the audio?
If it says it's embedded I've never seen a case where it wasn't though I have seen wavs that didn't play.
If you can use
www.yousendit.com to send a copy I can take a quick look. Won't cost you anything for a few minutes look but may (not without asking of course!!) if it needs studio time to fix the wav file.
john ATSIGNHERE pptalchemy.co.uk