Arm/Disarm by computer

I am using a joystick in the mission planer to control the boat, every thing is working fine, but when I select the button on the software Arm/Disarm, it gives me a message sayng that the MAv did not recognize the command. I am using the HKPilot32 from HobKing. SO the only way I can Arm/Disarm is using the switch in the navigation HKPilot32. Any one had this problem before?

What version of Rover firmware are you using? And what version of Mission Planner?

Thanks, Grant.