Thread:Extension talk:Scribunto/Lua error: language code ' lang ' is invalid./reply (4)

I see the issue. It looks like you copied a bunch of templates and modules from Commons. Commons does weird things with interface messages, though, which is why you see all kinds of weird text in angle brackets. Unless you have a good understanding of MediaWiki's i18n system, using those sorts of templates from Commons probably isn't a good idea. As a band-aid solution, undeleting http://bicyclesworkintheworld.com/MediaWiki:Lang should work. (Why did you ever delete that in the first place, by the way?)