Folgertech FT-5 : Does not seem to be reading G-Code correctly
The image shows that somehow steps in Y direction (under the assumption that you have taken the photograph from the front) are missed. 

Missing steps can be caused by too high settings for acceleration and jerk, too much friction on the undercarriage or the belt assembly, undercarriage catching something at a certain point, too less current through the stepper.

You could increase the torque on the stepper by increasing the Vref of your stepper driver is you have separate stepper driver modules, or a adjustment screw on the printer controller board. Furthermore reduce the acceleration and jerk settings and check the undercarriage for stick-slip movement by disconnecting the belt, then reconnect the belt and check for friction of the pulleys.