Hahahaha!! Yeah!! All tutorials have failed (or maybe WE have failed). As I said before, I also used the french page (which I translated to English with Google). Well, Salazaar, at least we're not alone. There's a whole crew of classmates of mine which have the same problem.

Some have already given up and started using GTK (which, to me, seems a lot more complicated to use). As soon as somebody has an answer, I will post it.

By the way, I know nothing of C++, so that main.o thing mekase me go "WTF????"