Adding a LPT port in windows NT 4.0

I need to add an additional parallel port for a zip drive on a IBM 300PL computer running Windows NT 4.0. We have a software key on the existing port, which does not alow the zip drive to operate properly. I have installed many of these with no problems under windows 95/98, but the port is not recognized in windows NT. Is there something I’m missing, or a trick to getting NT to recognize the port?