Reply to Numark mixtrack pro running on traktor pro

Ok so I have been using my mixtrack pro for about 4 months now and recently made the transfer from VirtualDJ to Traktor Pro 2 after buying the Kontrol x1. Now I'm having an issue... I cannot cue music though my headphones! I have the settings on Traktor optimized to use this controller but I'm not getting any sound through the headphone out.

I am using a Numark Mixtrack Pro along with a Traktor Kontrol x1 on an iMac with Traktor Pro 2. Now I have 2 questions: 1) How Can I fix this? Is there a way I can use the headphone out on the Mixtrack Pro? and question 2) If I can't use the headphone out on the Mixtrack Pro, is there another way I can listen to and cue up the next song before it plays through my PA system?

Any help is much appreciated as this is driving me insane!!!!! Not only that but trying to beatmatch through my PA while playing music at a party is NOT an option for me! PLEASE HELP!!!