mail() and IIS5 - newbie question

I'm trying to incorporate the php mail() function in an application I am writting. I'm running Win 2000 Server. I've set up a new remote domain named localhost under IIS Admin and I've checked the Allow incoming mail to be relayed to this domain option. I've added the following to the php.ini [mail function] ; For Win32 only. SMTP = localhost I'm using the following script which I'm running from the DOS command line. <?php /* Display a text message */ $myname = "Me Myself"; $myemail = "myemail@earthlink.net"; $myreplyemail = "myemail@earthlink.net"; $contactname = "Mister Contact"; $contactemail = "myemail@earthlink.net"; $message = "hello from happy me"; $subject = "A mail not refused by Hotmail"; $headers = "MIME-Version: 1.0\r\n"; mail($contactemail, $subject, $message, $headers); ?> I get the following error message... D:\php>php email.php X-Powered-By: PHP/4.2.2 Content-type: text/html PHP Warning: Server Error in D:\php\email.php on line 16 Any ideas on where I'm going wrong? I am new to IIS and PHP.