Reply to Pre Que Probz

Hey guys, I've run into a little problem here. I can't pre que. All in hear in my headphones is the master.(the master is also coming out of my speakers) So wherever the cross fader is, thats what i here. I'm using Traktor pro 2, a macbook pro, a mix track pro, and the sony mdr-v700 headphones. Anybody have any idea as to why this is happening?

*Edit* Also I have a gig toevening so any help is appreciated!