The GWS ESC's need to see the throttle at full off before they will arm and start working. Make sure the throttle is full off before applying power to the receiver/esc, then after waiting for the gyro to stabilize, and with the throttle still off, move the rudder stick full left for a second or two. If this doesn't work, then you may have to adjust the endpoints on your transmitter, to make sure the ESC's see both the throttle and rudder channels at zero.

Jeff