Except I can't get it to work. I've checked and re-checked everything, and as far as I can see, all the components are placed correctly. I can't find any fault in my soldering work.
Acting on the advice of kees_s, I changed the parallel port settings in the BIOS (there are four different modes), but to no avail.
So now I'm modifying a RS232-experiment board that I built to include a EEPROM. If everything else fails, I'll just do my bit-bashing through the serial port and a PIC.