Hi Daniele,
from a unix point of view, it sounds like the file permissions are still wrong.
Things to check:
the actual webuser from the apache httpd.conf file.
Make sure that the user in there is actually wwwrun.
also go into the design/site_name/override/templates directory and check the files in there to make sure they are the right permissions. Test the permissions by becoming the user and creating a file. eg "su - wwwrun" and "touch foo" Also check your apache logs, the error log may tell you whats wrong.