If the motor won't run the wheel when the throttle is depressed, the most likely cause is that the minimum speed of the bike has not been reached.  A safety feature of the Omni Wheel is that the bike is required to be rolling forward a 1 MPH to engage.  Simply begin some forward movement and then depress the throttle  (if the bike is inverted and the wheel is being tested, simply spin the wheel in the forward direction of rotation and then depress the throttle).