wav files

i just got my mpc 500 and im trying to load my samples from my computer which are .wav files and at first they would load and i could assign them but for some reason it speeded it up really fast to where i couldnt understand it...so i deleted the sample off the card and now when i put new ones on i cant assign them..the mpc says unknown file format...can somebody please gimme a little help with this...im usually on AIM if you can help me there
AIM - cuetippig

k i tried and it still dont work
it still says unknown file type or whatever
do i need to change any settings on the mpc or should i just be able to play it

mk could it maybe be the program i am using
as in just what kind of wav they export
i am using audacity

ok so is audacity ok to use then?
i am importing and exporting wavs from audacity
so all i am using is wav files
and all im wantin to do is load samples in

So, I didn't want to start a new thread, so I searched for wav convert, and this came up. Anyway, question is, what is the best program around for ripping CD's/flac/mp3 /etc to WAV? I assume audacity since that is what ya'll are using, but I figured I'd ask anyway.