u might try to make another folder with index file in it and see does it load it up? I would check .htaccess files and .vhost files becouse something is maybe geting override. U might want to try also to change site info in ispconfig so it remakes the .vhost file or try adding the
Options Indexes FollowSymLinks
or try with this command
to force loading of that file before listing directory.
Hope it helps
EonTek.rs - System Engineering