(you should donate! thorough rails 3 documentation would be great!)
...I came to an answer.
My problem was that I'm on Windows, and I installed ruby in the
program files directory. big mistake. the "F" is getting interpreted
because of the space in "Program Files"!
I had to reinstall Ruby right in C: like i should have (so it's C:/
Ruby). This also meant I had to reinstall RubyGems and Rails, but
hey, you have to tear a building down if it was built wrong in the
first place.