Problems loading samples

So I have had the MPC500 for some time and I love it. Apart from using it to sample/make beats, I also happen to be a DJ and I will throw some wierd sound effects on it- lately ive been DYING to get these samples on it, but when I load them onto the MP theyll show up in the folders when hooked up to the computer but not on the MPC. OR if they show theyll be "INVALID FILE FORMAT" or something else or END OF FILE. This is not the first time this happens. This is the group of samples i want--- http://www.vyb3.co.uk/vyb308/index.php?vyb3=sounds
Im pretty sure there Wavs and they should be 16-bit and everything else, if anything (this is gonna sound ridiculous) but maybe the samples have like a watermark or theres something about the integrity of them that does not allow them to be put on an MPC. Please help me out!!!!