They would need to be in
/var/lib/asterisk/sounds/it/
for Asterisk to know where to find those files , re-install your language files in an acceptable location and ensure they have the right "permissions".
Maybe
http://www.voip-info.org/wiki/view/Asterisk+sound+files+international
will help.
Any missing files will be played from your
/var/lib/asterisk/sounds/en/ or possibly /var/lib/asterisk/sounds/ if not in "en"
directory.