It seems your latest update broke compatibility with the native Itch.io client. The installer works independently, but the actual client fails to parse a valid install package.
Viewing post in Oh So Hero! Pre Edition II comments
Fixed flawlessly! Thank you very much.
Yeah, itch has had a client of its own for a bit now. I have no experience as a creator on it, so it may or may not help you there, but as a user one of the things it has is sandboxing the applications you install through it to help safeguard your system. That's not on by default, but still a very conscientious offering on the platform's part, particularly given the nature of many of the projects hosted.