Found the problem, finally!
Sorry, it was really our fault: a file in the installer wasn't updated
Many users have the correct file though, it depends when it was downloaded, that's why so few reported it.
To fix it quickly, download the attached file, and replace the file with the same name in the following folder:
You can simply download the 1.2 Updater (see the Sticky post above), or the Full installer, which have been both updated.