You didn't say if they're EXS formatted or not, but if they are then you have to see if they are in the app support in the Macintosh HD drive or in the app support in the user folder. If it's in the user one where it should be, then the only suggestions I have is to upgrade to Pro or if you have a ppc mac, get logic express 6.4 from ebay and use the exs instrument editor, as it has the exsp24 sampler, but for some reason it still allows you to create your own instruments from audio file like WAV, AIFF, & REX. I hope this helps