Custom sounds not working ingame.

I can preview and hear the sound just fine, but in-game, when the sound is queued to play, I get this in my console:
"S_StartSound: Failed to load sound 'tetris\tetris-saferoom.wav', file probably missing from disk/repository"
It's a 22050hz, 16bit stereo .WAV file. I have que points, saved as the same name as the original sound and in the same folder as they should be, and I still get this. Could somebody please help me? I would really appreciate it.