Since this is not something we hear of, I don’t have a canned answer to give you (on how to fix this). So I’ll have you try a few things and see how far we get.
1.) Run Windows Update. Make sure the system is up-to-date with all Microsoft Windows updates, hot fixes, etc. The panel use uses the .NET Framework 4.0. So you will want to make sure all .NET updates and fixes are applied.
2.) Repair Rhino. To make sure all of Rhino’s components are installed correct, repair your Rhino installation by running Control Panel > Programs and Features > Rhinoceros 5 (and Rhinoceros 5 (64-bit) > Repair.
3.) Check the logs of any installed virus detectors or malware applications to see if they are blocking any Rhino components.
There may be more to come…