Thread:Project:Support desk/All images with diacritics in name disappeared after some update

Some time ago all images, using any characters with diacritics in name disappeared, images with standard characters work normally - I have 3 instalations of mediawiki on our server and it happens in all of them:
 * http://www.enviwiki.cz/wiki/Speci%C3%A1ln%C3%AD:Nov%C3%A9_obr%C3%A1zky
 * http://www.czp.cuni.cz/vcsewiki/index.php/Special:NewFiles

Mediawiki 1.16.4, Apache/2.2.17 (Win32) DAV/2 mod_ssl/2.2.17 OpenSSL/1.0.0a PHP/5.2.17

There is probably some coding problem when storing the images, because images are stored on server, but with wrong names. For example: "Letňany.jpg" is stored as "LetĹany.JPG".

Thank you for any ideas.