ho già i privilegi di scrittura.
nelle istruzioni mi dic anche questo:
CHMOD on Windows servers

Not all platforms understand the CHMOD command, Windows servers for example don't support CHMOD. Most Windows hosting plans come with a folder called "cgi-bin" or "cgi" which is pre-configured to allow files being writable by scripts. If you are having trouble installing your scripts on a Windows server (get an "Please CHMOD to 666" error) try installing the script within your "cgi-bin" directory!

ecco il link del tutorial:http://www.phpjunkyard.com/ftp-chmod-tutorial.php