Код для отправки электронной почты не работает

Когда я пытаюсь выполнить следующий код для отправки по электронной почте сведений о форме контакта, он не выполняется должным образом. Вместо этого, когда нажата кнопка отправки формы контакта, она просто показывает исходный код в браузере. Что не так?

<?php error_notice(E_ALL^E_NOTICE); $firstname = $_POST['fname']; $emailaddress = $_POST['eaddress']; $mobile = $_POST['cellno']; $phone = $_POST['landline']; $country = $_POST['ucountry']; $city = $_POST['ucity']; $subjects = $_POST['usubjects']; $message = $_POST['umessage']; // EDIT THE 2 LINES BELOW AS REQUIRED $email_to = "abc@example.com"; $email_subject = $subjects; function died($error) { // your error code can go here echo "We are very sorry, but there were error(s) found with the form your submitted. "; echo "These errors appear below.<br /><br />"; echo $error."<br /><br />"; echo "Please go back and fix these errors.<br /><br />"; die(); } // validation expected data exists if(!isset($firstname) || !isset($emailaddress) || !isset($subjects) || !isset($message)) { died('We are sorry, but there appears to be a problem with the form your submitted.'); } $error_message = ""; $email_exp = "^[A-Z0-9._%-]+@[A-Z0-9.-]+\.[AZ]{2,4}$"; if(!eregi($email_exp,$emailaddress)) { $error_message .= 'The Email Address you entered does not appear to be valid.<br />'; } $string_exp = "^[az .'-]+$"; if(!eregi($string_exp,$firstname)) { $error_message .= 'The First Name you entered does not appear to be valid.<br />'; } if(strlen($message) < 2) { $error_message .= 'The Comments you entered do not appear to be valid.<br />'; } $string_exp = "^[0-9 .-]+$"; if(!eregi($string_exp,$phone)) { $error_message .= 'The Telphone Number you entered does not appear to be valid.<br />'; } if(strlen($error_message) > 0) { died($error_message); } $email_message = "Form details below.\n\n"; function clean_string($string) { $bad = array("content-type","bcc:","to:","cc:","href"); return str_replace($bad,"",$string); } $email_message .= "First Name: ".clean_string($firstname)."\n"; $email_message .= "Last Name: ".clean_string($mobile)."\n"; $email_message .= "Email: ".clean_string($emailaddress)."\n"; $email_message .= "Telephone: ".clean_string($phone)."\n"; $email_message .= "City: ".clean_string($city)."\n"; $email_message .= "Telephone: ".clean_string($country)."\n"; $email_message .= "Comments: ".clean_string($message)."\n"; // create email headers $headers = 'From: '.$email_from."\r\n". 'Reply-To: '.$email_from."\r\n" . 'X-Mailer: PHP/' . phpversion(); @mail($email_to, $email_subject, $email_message, $headers); ?>