That's likely why it's throwing those errors, then - the reference to SetCenter is in my own code. I'm using the current headers as far as I know. I'm still a bit puzzled by the multiple definition error, though.
EDIT EDIT:
Nevermind, I think I was just getting a different compile error first. I'm still getting the "multiple definition of `sf::Font::~Font()'" error. If I don't use any Font functions in main.cpp, it doesn't give me this error. Is there any way I could fix this?
As well, now that I look at it, I'm getting these errors in the linking stage, so that means that you're right about the headers being outdated. That said, I've checked the headers, and they're definitely the new ones. Maybe I'm experiencing some strange Code::Blocks quirk?
EDIT EDIT EDIT:
Okay, I found the problem. Code::Blocks had an old version of SFML set as a default search directory, but I had forgotten that. It doesn't show up in the project settings, so I didn't notice. It was getting outdated headers from there, but a new version of the library, which was causing the problems.
Thanks anyway!