emc input scale reboots

I'm running EMC Linux 2.4.18rtai on a 166Mhz bix ( cuz my new box
was faster but couldn't run this kernel, and the new UniSTuttgart
bundle didnt include Steppermod or source :-( )
Anyways, I got it up and moving my ShopTask with 650 ozinch steppers
from Tim. I went to et the scaling factors, and laid a dial vernier
on the X way, Zeroed the machine and moved in 0.1" on the dial
vernier. Then I got the reading from the DRO, it was 2", so I went
back and checked, make the machine move 1 step using testppt, ok,
it's true I got "half tenth' steps, 1 step is 0.00005".
No big deal, just a number, so enter Input_Scale as 20000, right?
it takes 20,000 steps to make 1 inch? well the machine rebooted
just before the TK_EMC screen appeared. Many times.
I changed the number to 10,000 and got a very sluggish, but working
system that gives me 1/2 scale output.
What to do?

BTW: thanks to the EMC guys for making such a nice package. I see
a lot of rants, and then I whine, but they did a great job!

regards, TomP