Step motor turns only 1 way

Hi everyone, I've just set up my Xylotex drive with my 6 wire
2amp/phase motors wired in full-winding mode. I'm using TurboCNC to
just see if the motors turn. I can jog the motor, but it will only
turn in one direction. If I jog the motor in the opposite direction,
it still turns, but still in the same direction. Any idea what's
wrong? Thanks in advance.