the link seems to have an extra slash at the end, http://elm-lang.org/ works for me.

Can you specify which link you visited? Or what platform you are on?

Which suggests the site is generated in some unsafe way that could possibly be exploited.

While this massive bit of speculation is exciting, this is not the case. It is a compiler error indicating that the poster somehow compiled an Elm file without any content in it. I suspect my servers are having a bad time right now, so the file may have been only partially read for some reason.

I am trying to scale my servers up now!

You get the error when you go to http://elm-lang.org//