EMC and freqmod

Is the EMC freqmod used only for closed loop stepper control or will it
work on a simple open loop system? I was successful running steppermod
but always get following errors when I try the freqmod.

Also, I am having a problem with my RTLinux. After booting my system I
can run EMC fine for about an hour then system response starts to slow
down eventually coming to a complete stop. I have to do a hard reset of
the system and can run for another hour or so. Memory leak in the RT
system?

I am using RedHat 5.2, with upgraded kernel headers and source from the
RedHat site.
kernel-headers-2_0_36-3_i386.rpm
kerner-source-2_0_36-3_i386.rpm
Real Time patch release 9.
EMC 07-June-2000

Thanks,
Terry