Good idea on the cable...

I don't use the LPT port myself (for a lack of one), but there are some settings in BIOS to do with the printer port. Try turning on EPP if it isn't already. However I don't think this is the cause, since it would probably work regardless if it was EPP or not. Worth a try though.

I have the same drives and the switches are OFF, OFF, ON, ON, OFF, OFF, ON, ON. This gives half current (my series wound motors only need half), and 1/8 stepping.

One last thing I would double and triple check the way you have wired the motors. And if you have tried parallel wiring, try series and vise versa.

Dave.