Yeah we need more info. What DJ software you are using, what ASIO version you have... are you using it in all MIDI, or a combination? Did you check the switches in the back and make sure everything is set correctly? You need to set it to PC MIX if you are running any MIDI channels.
My first thought is that you don't have the channel matrix switches set to different channels. For instance, I use mine as an all MIDI controller, so all 4 channel selectors are on MIDI. But when/if I need to hook up something like a CD player, I just change the input selector to LINE (1,2, etc).
Second thought is the ASIO drivers. You should update to 2.20. If you can't find it online (believe me, its harder than it should be), I can send it to you.