See http://lists.fedoraproject.org/pipermail/websites/2012-October/020019.html
There should be something wrong on the apache conf. We already hit this issue before, dunno how to resolve it now.
Same for start or other websites..
I think its related to the languages.conf file. Its possible the greek language code isn't on the list.
Ticket closed as it's the same issue as #139. Please continue there to provide more details for the greek language, hope to fix it soon.