[Plugin: Automatic Newsletter] Can not activate it

Hello,

I get this error:

Warning: require_once(Mail.php) [function.require-once]: failed to open stream: No such file or directory in /var/www/web27/html/wp-content/plugins/automatic-newsletter/autonews.php on line 10

Maybe you can help?

http://wordpress.org/extend/plugins/automatic-newsletter/