Since the last version of WP I’ve experimented a problem which gives me tons of headache.
It happens that files which contain weird characters in their name such as: “é, ç, ñ, ô, ü…”, are correctly uploaded and showed in some of the browsers: FF, Chrome; but they present problems in others such as Safari, which can’t open them.
I recommend WP change file names at uploading point, replacing weird characters by friendly ones.
It’s not a big deal and helps internationalising the platform.