NEED HELP SERVO ENGAGE

[cristian gabor]

hi
i vave had my plasma table runing for 6 monts on belts
and decided to go for rack & pinion drive. all worked fine until my servos do not engage anymore .
I have a buton on my controller (logitroll 20 amp ametek servos )that if i push up for 3 sec it engages (activates ) the servos or from active mode if pushed down dectivates the servos.
when my computer is of or if i unplug the parallel cable from computer ,i can activate the servos everything is ok
but when the computer is on (does not mater if mach is runing or not)the servo do not engage.
when i push the buton to activate the servos they try to move and deactivates
or if i keep the buton presed the 3 axis move rapidly and get deactivatad and move again (hi speed very short moves ) and so on until i release the buton.
there is another situation when i unplug the parallel cable, activate the servos then plug back the cable and play whit it lyke everything is ok

[cristian gabor]

the xml file