so you have a tt, and a dj mixer i assume.

in that case, you are going to need to get something like this:
http://www.zzounds.com/item--MONMDJCR

that will allow you to hook the outs of your dj mixer to the inputs of your soundcard.

while you are waiting to solve the probelm though, you can just take a reg 1/4 cable and hook it up to the soundcard and the headphone jack on your mixer. you wont get any fader action, but you can do some mono sampling untill you get the right cable.