Hmm. The most common problem is that Poser's sound engine will only accept a single channel .wav file. If it a stereo, or Ghu forbid a 5:1 sound file, at best it will refuse to function and throw cryptic errors about unrecognized format. Just a plain old 8 bit mono .wav is all that works in the Poser app. The second most likely is that the codec being used isn't accepting the sound input. This could be for numerous issues, including only being a 'partial' codec (it was designed specifically to only decode; you have to buy the encoding part).