Rhino Scripts Errors in Rhino 6

Dear Sir, This is to inform that im facing problem while clicking on assign materials when working in Rhino 6 Software as the below attached errors are getting displayed repeatedly and as a result simulation is not getting run. I request to please provide solution for this problem.

I never faced this error.

Based on the muck on your screen and the fact it is a photo, not a screenshot, am I guessing correctly that this machine is on a workshop floor? Is it connected to a fabrication machine? What exactly are you doing to “assign materials”? Is this in a machining plugin that needs materials assigned to setup the machining?