Hi psopa,
Did you modify any of the files? Please make sure that at the beginning or at the opening of php tag, no blank lines or spaces or other characters (seen or unseen) preceding it. Some editors, when they save a file as UTF-8, stick extra characters into the file at the very beginning (the format doesn't require it, but they do it anyway). Then refuse to show you those characters when they display the file. To see if your editor is one of these, try saving an empty file and seeing how many bytes it takes up.