please me on mail function

Dear friend, I am using PHP 4.3.4 version. Please tell how to unpload a mail function. Error comes on executing mail function is "mail(): SMTP server response: 550 5.7.1 Unable to relay for softengg@iclcl.com in C:\Program Files\Apache Group\Apache2\htdocs\testprodigious\MAIL\mail_enquiry.php on line 30 " Scprit used is <? /* recipients */ $to = "softengg@iclcl.com"; /* subject */ $subject = "Automatic Weekly Reports of Marketing from Prodigious"; /*making message body */ $message ="Wekly Reprot"; /* To send HTML mail, you can set the Content-type header. there header are nessare for maing table in php and even for html pahe without these header only script will send in mail no brwser look*/ $headers = "MIME-Version: 1.0\r\n"; $headers .= "Content-type: text/html; charset=iso-8859-1\r\n"; /* and now mail it */ mail($to, $subject, $message,$headers ); ?> I will be grateful to you. With Best Regards «·´·.(*·.¸(·.¸ ¸.·´)¸.·*).·´`·» «..Er. Kunal Aggarwal ..» «·´·.(¸.·*(¸.·´ ·.¸)*·.¸).·´`·» Software Engineer ICL Certifications Limited 372, Industrial Area Phase 1 Panchkula Haryana India Voice Talk:-+91-98159-65988(Mobile), +91-0172-2563358 (Office) * 24, +91-0172-2563358 (Fax) Email: softengg@iclcl.com Website: www.iclcertifications.com