-r, --rig-file=device
Use device as the file name of the port connected to the radio.
Often a serial port, but could be a USB to serial adapter. Typically /dev/ttyS0, /dev/ttyS1, /dev/ttyUSB0, etc. on Linux, COM1, COM2, etc. on MS Windows. The BSD flavors and Mac OS/X have their own designations. See your system’s documentation.
The special string “uh-rig” may be given to enable micro-ham device support???
"C:\Program Files\hamlib-w64-4.5.5\bin\rigctld.exe" -m 1023 --rig-file=COM6 -s 9600

Have you tried v.1.23 yet? I removed the DUAL_WATCH command from the rigctld.exe initialization, now it should work with your radio.