Kwikee slide out problem - Stall on Rear Actuator only

My 2003 Minnie 24F has problem with the slide out again. The slide out wont extend. Battery is fully charged and the brake is on. The error code is "Stall on Rear Actuator only" (# of flashes = 6) . The slide out is made by Kwikee . Below is the manual .

Has anyone had this issue before and how did you fix it ?

thanks in advance

http://support.powergearus.com/techdocs/DigiSyncServTraining%20Module.pdf