Thread:Project:Support desk/Invalid Database Type Error During Installation/reply (2)

While you're on it, upgrade to 1.21.2 which has been released very recently ;)

That's strange. From what I've tested, it seems like PHP doesn't get any of the form input you put on the installer pages, even the language selection of the first screen. It's simply ignored. And that's the cause of the error message you see (MediaWiki expects you to choose a DB engine and you provided nothing).

Maybe a problem with PHP configuration?