EMC freqmod.o question

I have been using EMC steppermod.o for some time to control a
Sherline Mill with a simple Stepper Word step direction controller.
When I try using freqmod.o the motors run much smoother, but I
eventually loose control of the Y and Z axis expecially when homing
or sometimes when starting up EMC. The parallel port appears to be
locked up and completely shutting down and turning off the PC power
corrects the problem. It is not the parallel port...changing it to
another brand has no effect. Could it be that my PC is not fast
enough for freqmod.o ? (450 Mhz Pentium, Intel BX Motherboard, 512
meg RAM.) I have experimented with the Sherline Mods and played with
their freqmod.ini files and get exactly the same result. Does anyone
have any ideas?