remember my joke about this happening in xp too? this kind of sounds are in wav format on xp
very few apps today use wav as file of choice, the last app i saw using this was some games around 2004, recently is ogg, mp3 or any other compressed and easy to reproduce file, the size matters on audio files
"Well, my .wav files were working before I upgraded to KDE4"
kde4 is very different in some details compared to kde3, this is one of the sides that sometimes is not as friendly as kde3 but since we are still on the early versions, lets see how it evolves