Risco Lightsys 2 - Can't get CS to connect with RS-232

Hi. I have a Lightsys2 in use, which works quite well. It's connected to IP, and I use the Configuration Software to configure it. In the meanwhile I also got an RS-232 cable I want to be able to use, just in case IP fails or so. I can't get CS to connect to it. From the manuals as well as the FAQ, the settings are: 115200,8,N,1. I've set CS up like that, but still no go. When I use putty and connect to the COM port, and power-on the system, I see the bootloader booting up, and a lot of info shows on the screen. In fact it seems like it's some Windows CE board or something, it doesn't resemble linux. But anyway, given that I can actually see that info, my cable must be correct.

CS gives this error though:

The Configuration Software manual I have does not list error 20005.

While I can access the unit by IP, I'd still like to be able to use serial as well. Would anyone know how to get this to work? Thanks!