First, my English is not so good for detail describe the machine.

Basic ideas I find on Luberth Dijkman's site.

The steppers (12V dc, 1,8 per step, unipolar) a from 5,25" floppy disk drives.
The X axis was built of an old HP ScanJet.

With small program writen in QBasic and 3axis stepper motor driver with ULN2803 ic's via the parallel port, motors work separatly.

I hope that with your Software the three axes will work together.

I use Windows 98 (Second Edition), AMD-K6 processor, 32 MB RAM.