I don't operate nor am I familiar with Kenwood stuff though I think they have some very nice equipment. I've found that the hardest part of HRD for anyone is connecting to the radio and more times than not it tends to be the cable driver software. You might want to try and see if there's any newer versions of the driver available. I use RT System cables and software and I've had good success. I know you can connect to the radio with Kenwood software but it's worth a try. Also try using the "auto-detect" feature when choosing com port (even though you're using USB port) and baud rate settings. Hope this helps.
73 Randy AJ7G
I use the FTDI chipset. But as Randy mentioned, the settings are incorrect because your Kenwood software can connect.