When I tried to uninstall ChemOffice, I got four alert messages, each of which was titled "Microsoft Forms" which said, "Could not load an object because it is not available on this machine." while the installer window behind it said "Status: generating script operations for action:"
It seemed to then proceed normally, and when all was done, my ChemOffice folder was removed.
The error seen pops up when the installer is attempting to remove the Excel Add-Ins. When it does this, it attempts to bring up an instance of Excel. If the XLA (ChemFinder for Excel) files are missing, the creation of the instance of Excel (if the Add-Ins were active) causes these error messages to appear. Basically, ChemOffice has been removed. You may get an error message the next time you launch Excel about missing Add-ins. If you don't, you will get one if you open the Add-Ins dialog in Excel and attempt to disable the ChemFinder for Excel Add-in because it is not there. When prompted by Excel, choose to remove the missing Add-In.