I'm pretty bad when it comes to figuring out stuff like this but if you have a mixer you can just connect the 'Line Out' of your PC to the input of your mixer. Then connect the Output of your mixer to the 'Record In' on the MPC.
Then just play the samples on your PC and sample them into your MPC from there. Well thats what I do
I guess this is a waste of time if you don't have a mixer though!
Hope it helps mate
