[PHP-INSTALL] [PHP-WIN] SMTP server response: 530 authentication required

The full error is as follows:

Warning: mail(): SMTP server response: 530 authentication required - for
help go to http://help.yahoo.com/help/us/mail/pop/pop-11.html in c:\program
files\apache group\apache\htdocs\send_simpleform.php on line 10

I receive the error above when I attempt to send mail via a PHP script.