MiKiL: Been reading this too and stumbled on same exception-error, just went ignoring-way.
Now that I look around it seems that galaxy serves updated version (v1.3) looking by
gogdb-entry (under Builds-tab) while offline package is at v1.0. I hope GOG pushes offline update soon if this is the case.
clarry: Thanks to your post, I got DrKitty to take it up with the product team.
Now we just wait.
EDIT: Offline installers for Windows & Mac are now version 1.3, for Linux it still shows 1.0L on my end?
Yup, 1.3 for Win & Mac and still 1.0L for Linux here too.