> I have used these programs for years with release 22.1. Upgrading to
> 22.6, I cannot make them work.
Yes, GAMS has changed the GDX API causing a lot of compatibility problems. Invert.exe is now part of 22.8. Eigenvector.exe somehow is not. If you are a client of Amsterdam Optimization contact firstname.lastname@example.org and they can give you access to 22.6 versions of both.