[Dx4win] 590S Port Problem

[n4dsp]

Radio/Start I receive an error message "i.e. BadLD-Specified comport 
doesn't exist. Radio error #1.

Serial Port specified for radio is in use by another device.
Select a different port for the radio or the other device."

But going to device manager/Ports I find the comport 3 being used by 
correct driver by Kenwood,
Silicon Labs CP210x to UART Bridge (com3).

For the 590S to communicate with dx4win I have to reboot instead of just 
clicking on Radio/Start.

Help!

john