Solution 1:

If "Runtime error 91: Object variable or With block variable not set" occurs after a DentalCAM 7 installation or Windows update, please see this related article:

Error while activating the 3D Viewer" Message Appears:

Solution 2:

Products Effected:  DentalCAM 7

Symptoms:  Runtime error 91 occurs when the user initiates a job calculation

Solution:  Runtime Error 91 could occur due to a  DMT.pdt file being possibly corrupted.  You can rename or delete the current DMT.pdt file and then

The file is located here:  c:\vhf\DentalCAM_7\DMT.pdt)