Maxnc and Gecko 201's

Morning all,
Well I am still having a little bit of trouble. With Cncpro
evaluation I have everything running spot on, but when I try and use
Maxnc and get all the calibrations correct it will only process the
first couple of lines and the program will lock up . Is it because
there are too many steps per inch and the computer cannot cope?( it
is only a 585 dx 100) It will fast jog and all ok! The only way I can
get the demo programs to run after that is to reload the software and
then it goes back to the default settings and will run all the
programs but not at the correct calibrations! I have to change them
again and then maxnc locks up again!. There are 20,000 steps per inch
in both the x & y and an incredible 45,134 per inch in the z axis!
Rmember it is ok with these in CNCPRO.Help anyone?
Mark