NUT on Windows with a very old USHA+ card - snmp-ups driver can't start

I realise this is a fairly niche topic, but perhaps someone can suggest something.

I'm trying to interface with a very old USHA card:

http://www.derungs-electronic.ch/files/USHA-_User_Manual_V1.00_EN.pdf

It's configured to support SNMP v1 via UDP 161 and SNMP support is enabled on the card itself. I'm running NUT on Windows 2016 Server, I've installed the only available Windows binary package 2.6.5-6 from NUT's website and it seems to be running fine. I've followed the manual for configuration but I'm getting stuck pretty much at the very start where the driver is being started, getting the following error:

Command (ran from cmd line with admin rights):

C:\Program Files (x86)\NUT\binupsdrvctl start

Result:

Network UPS Tools - UPS driver controller Windows -v2.6.5-5-7-g72f380c

Network UPS Tools - Generic SNMP UPS driver 0.70 (Windows...