@cardinal
I also suspect that when I did the world update that brought me this problem I was not able to update all packages that were supposed to be, because I did "emerge -auDN @world" but I left my notebook emerging all things and I went to college. When I got back I did not noticed at first but after I reboot my note, I realized that may some packages were not updated as supposed to be (as the case of PyGTK). Can this problem be caused by some package that were not installed properly on that world update?
Well, I do not know if it makes much sense but I am trying to figure out something that may caused this problem to me. Also, I do not know if it is relevant, but I do not use GNOME or LXDE and others stuffs like these, I use dwm.