Andy,
I can't provide a "specific" solution, but only (hopefully) point you in the right direction.
In a previous office where NT was used, we had to have a "network specialist" make a modification which was related to Lotus 123 Release-5 being 16-bit software, being used on NT which is a 32-bit operating system.
So the good news is that it is fixable, but the bad news is that you'll probably have to consult with an NT network specialist.
If my memory serves me correctly, I think the solution centered on setting up a separate "printer driver" which NT does not automatically come with or use for 16-bit software.
This seems like ANOTHER case where Microsoft places "sticks in the wheels" of those who PREFER to use "older" software. Lotus 123 Release 5 is an EXCELLENT example of PREFERRED software - because it is STILL FAR SUPERIOR to today's software - both Excel and later versions of Lotus 123.
Hope this helps.
Regards, ...Dale Watson dwatson@bsi.gov.mb.ca