Ubuntu server, PHP 5.3, connected via Samba to Windows server share. I am using file_exists() to check for availability of file on Windows machine. It returns false, although the filepath does exist. Meanwhile, file_get_contents() on the exact same filepath works fine. I'm wondering if it's a permission issue, since I'm having trouble configuring permissions of the files on the Windows share (it says I don't have permission to change permissions on them). When I look at the permissions through Nautilus, it says the user and group are both root, with 755 rights. I'd like to change the group to www-data, but can't seem to do it.