Please see the most recent updates in the "Where did the .com name go?" thread. Posts number 16 and 17.
Are you using a dedicated sound card? I've tried googling the error and it could be anything from needing to update sound card drivers if you are using one, restarting the windows audio service, or running your audio device troubleshooter through windows.
You may also try contacting the author or posting to FSDeveloper as I believe the individual is a member there.
Also, does this error occur outside of the sim if you try to play the wav file directly?