Gerber Dimension 200

Just got an older Dimension 200 with Omega 2.5 and ArtPath but having problems with the Z holding its depth. I set the cut depth maximum to .25 and after about 45 seconds into the job, it starts diving to around .5 or .75.

Can anyone help?

Thanks,
teemac

Upgrade the software, Had the same problem with Advantage 4.1. went to Omega and that cured it.