Warning: mail() [function.mail]

[zozzoozzz]

I have installed the oscommerce on my LOCALHOST, When I have to write a message in the "Contact Us" page, and click the "continue" button, the two warning lines appear:

 

 

Warning: mail() [function.mail]: SMTP server response: 530 authentication required - for help go to http://help.yahoo.com/help/us/mail/pop/pop-11.html in C:\AppServ\www\catalog\includes\classes\email.php on line 522

 

Warning: Cannot modify header information - headers already sent by (output started at C:\AppServ\www\catalog\includes\classes\email.php:522) in C:\AppServ\www\catalog\includes\functions\general.php on line 33

 

 

What causes the WARNING?

 

and how to modify it?

 

 

ANY helps will be appreciated . thanks