I find it hard to believe that you couldn't get ahold of Tom at Candcnc. You might also try to catch him on his Yahoo group.
I don't work with Wincnc, but from what I understand, you have to remove their driver card from within your PC, and just install Mach3. It will be assigned a parallel port from the setup menu.
I want to say that you will just have to get another parallel port card, plug it in to the motherboard, and assign it in Mach as well.
I have been told by a number of people that it is a simplistic process, and quite worth it in the end.
Good luck!
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
"If the women don't find you handsome, they should at least find you handy"
-RedGreen show.