I've had the same errors and been struggling with it.
I don't use codeblock (only the gcc compiler in command window), but I figured out my problem : you must respect a certain order when linking the libraries. The system, then the window, then the graphics if you only use <SFML/Graphics.hpp> in your include. However when in command line, you must specify them in the opposite order (draphics, then window, then system).
So, try inverting the order of your linked libraries in codeblocks (I see you've got little arrows on the right of the window, is that it?)