Mission editor problem

I used the mission editor once and it worked fine in windows 10. When I tried to run the sh3 mission editor a second time I get an error message 'The unit class CDAAPlatform from country Brazil not found in the platforms library.

Has anyone else found this problem and know a solution?

Alternatively, is their anywhere I can download it directly and put the compatibility patch over it? I don't really want to uninstall and reinstall the whole program again.

Thanks in advance!