OK, maybe I started a thread for the very same problem which was discussed in another thread. And, maybe, it was too cryptic that to get an answer.
We now fixed it in that way that we searched for a mainboard which has an inbuild parallel port (we found an affordable ASUS-board, and nowadays it's really hard to find such a board, who needs a parallel port any more!?).

Anyway,
best,
Tom