No sound coming out of headphones at any time

I am using a Numark Mixtrack pro 2, and am not getting any sound out of my headphones at any time. I have followed the instructions within the FAQ's however this has not solved the problem. Under the audio menu, I can only set up one output, with the name "Left/Right", but if I try to set this up on output two, it will delete it in output one. There is sound coming out of the speakers. Thank you.