This error means that the tablet is not communicating with the motors. Check the motor power supply to make sure it is fully plugged in and the green light is steadily on. Also check all wires going to the motors and the silver box to make sure they are secure. Make sure you have a surge protector on the motor power supply. If none of these are the solution, you can check the small black boxes located next to the motors. Simply flip the cover off of each box and make sure that all of the pin connectors are firmly seated.