I know it is an old topic, but i have the same problem with Rhino8 and RhinoCAM2024.
I have installed and repaired it multiple times and it is still not working.
Is there any solution for this problem?
I had a case where I had to uninstall RhinoCAM completely, including cleaning out the orphaned MecSoft entries in the registry. Once re-installed, the issue was gone. However, this was not in Rhino 8 so your results may differ. Might be a good one to throw to MecSoft support.