New Makerfarm i3v 12...middle of prints aren't sticking

I've finished assembling my new Makerfarm i3v 12 and when doing my test prints I've tried printing with glass and hairspray and then glass and tape, but I can't get prints to stick to the middle of the bed. What am I missing?

Picture of middle of prints not sticking (print is a little messy because I was making adjustments in real time, but you can clearly see the middle not sticking. I can visually see a gap under the line of filament as it goes across the middle.

http://i.imgur.com/3qv8XLN.jpg