Check the Camera Settings | Input tab, set Gun Sensor to None. This turns off the wired start connection. The wired start and wireless start are two separate connections in the system and are independent of each other.
Check that the RadioLynx is configured correctly. Open the Camera Settings | RadioLynx tab and be sure the selected item matches the physical connection of the RadioLynx receiver (C-Box, camera back, radio port etc).
If you need additional help, contact technical support.
Keywords: armed, error, arming, Radiolynx, gun sensor