use my fsbext tool (latest version is 0.2.11):
http://aluigi.org/papers.htm#fsbextusually when winamp doesn't play a wav file is due to the codec used in it, for example imadpcm that as far as I know vlc plays otherwise try with mplayer.
if you have doubts try to upload the smaller of the wav extracted with fsbext on sendspace.com so that I can take a look