Contact Form Problems

I'm having issues with a contact form that typically works great, but is giving me trouble on a Godaddy VPS CentOS 6.3 server.

Here's the code I'm using for my form:

<?php
  // contact form - process form
  if (@$_REQUEST['submitForm']) {

    // error checking
    $errorsAlerts = "";
    if (!@$_REQUEST['firstname'])                { $errorsAlerts .= "Please enter your first name!<br/>\n"; }
    if (!@$_REQUEST['lastname'])                { $errorsAlerts .= "Please enter your last name!<br/>\n"; }
    //if (!@$_REQUEST['title'])                { $errorsAlerts .= "Please enter your title!<br/>\n"; }
    //if (!@$_REQUEST['company'])                { $errorsAlerts .= "Please enter your company name!<br/>\n"; }
    if (!@$_REQUEST['address'])                { $errorsAlerts .= "Please enter your address!<br/>\n"; }
    //if (!@$_REQUEST['address2'])                { $errorsAlerts .= "Please enter your address 2!<br/>\n"; }
    if (!@$_REQUEST['city'])                    { $errorsAlerts .= "Please enter your city!<br/>\n"; }
    if (!@$_REQUEST['state'])                    { $errorsAlerts .= "Please select your state!<br/>\n"; }
    if (!@$_REQUEST['zipcode'])                    { $errorsAlerts .= "Please select your zipcode!<br/>\n"; }
    if (!@$_REQUEST['phone'])                    { $errorsAlerts .= "Please enter your phone number!<br/>\n"; }
    if (!@$_REQUEST['email'])                    { $errorsAlerts .= "Please enter your email!<br/>\n"; }
    else if(!isValidEmail(@$_REQUEST['email'])) { $errorsAlerts .= "Please enter a valid email (example: user@example.com)<br/>\n"; }
    if (!@$_REQUEST['message'])                    { $errorsAlerts .= "Please enter a message!<br/>\n"; }

    // send email user
    if (!$errorsAlerts) {
        $from        = $_REQUEST['email'];
        $headers    = 'MIME-Version: 1.0' . "\r\n"; 
        //$headers    .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n"; 
        $headers    .= 'Content-type: text/html; charset=utf-8' . "\r\n";
        //$headers     .= "Content-type: text/html\r\n"; 
        $headers    .="From: $from \r\n";
        $to            = "webdev@domain.net";
        $subject    = "{$_REQUEST['firstname']} {$_REQUEST['lastname']} submitted a message at {$_SERVER['HTTP_HOST']}";
        $message    = <<<__TEXT__
<div style='background-color:#006BAF; padding:24px; font-size:22px; font-family:Arial; color:#FFF; margin-bottom:12px;'> Please contact {$_REQUEST['firstname']} {$_REQUEST['lastname']}
</div>

<div style='padding:24px; font-size:14px; font-family:Arial; color:#003A46; margin-bottom:0px;'>
<strong>First Name:</strong> {$_REQUEST['firstname']}<br />
<strong>Last Name:</strong> {$_REQUEST['lastname']}<br />
<strong>Title:</strong> {$_REQUEST['title']}<br />
<strong>Company:</strong> {$_REQUEST['company']}<br />
<strong>Address:</strong> {$_REQUEST['address']}<br />
{$_REQUEST['address2']}<br />
<strong>City:</strong> {$_REQUEST['city']}<br />
<strong>State:</strong> {$_REQUEST['state']}<br />
<strong>Zipcode:</strong> {$_REQUEST['zipcode']}<br />
<strong>Phone Number:</strong> {$_REQUEST['phone']}<br />
<strong>Email:</strong> {$_REQUEST['email']}<br /><br />
<strong>Message:</strong> {$_REQUEST['message']}
</div>

<div style='background-color:#CFE2A7; padding:24px; font-size:14px; font-family:Arial; color:#FFF; margin-bottom:12px;'>
The user who sent this message had the IP address {$_SERVER['REMOTE_ADDR']}.</div>
__TEXT__;
      // Note: The above line must be flush left or you'll get an error
      // This is a PHP heredoc.  See: http://ca2.php.net/manual/en/language.types.string.php#language.types.string.syntax.heredoc

      // send message
      // $mailResult = @mail($to, $subject, $message, "From: $from");
      // if (!$mailResult) { die("Mail Error: $php_errormsg"); }
      
      // send message 
      $mailResult = @mail($to, $subject, $message, $headers); 
      if (!$mailResult) { die("Mail Error: $php_errormsg"); }

      //
      $errorsAlerts = "Thank you for taking the time to contact us. A representative will be in contact.";
      $_REQUEST = array(); // clear form values
    }
  }   // contact form - end process form
?>


When I submit the message, it comes across as raw source code as see below and there's no from email address produced:

Content-type: text/html; charset=utf-8

From: johndoe@domain.com

<div style='background-color:#006BAF; padding:24px; font-size:22px; font-family:Arial; color:#FFF; margin-bottom:12px;'> Please contact John Doe
</div>

<div style='padding:24px; font-size:14px; font-family:Arial; color:#003A46; margin-bottom:0px;'>
<strong>First Name:</strong> John<br />
<strong>Last Name:</strong> Doe<br />
<strong>Title:</strong> CEO<br />
<strong>Company:</strong> ABC Company, Inc.<br />
<strong>Address:</strong> 1234 Main Street<br />
Suite 100 #200<br />
<strong>City:</strong> Atlanta<br />
<strong>State:</strong> GA<br />
<strong>Zipcode:</strong> 00000<br />
<strong>Phone Number:</strong> 000-000-0000<br />
<strong>Email:</strong> johndoe@domain.com<br /><br />
<strong>Message:</strong> test message 3
</div>

<div style='background-color:#CFE2A7; padding:24px; font-size:14px; font-family:Arial; color:#FFF; margin-bottom:12px;'>
The user who sent this message had the IP address 00.000.000.000.</div>

The DNS settings for the domain are set to use Godaddy's email servers - not the VPS's email, so the VPS server is relaying the message to the Godaddy email servers. Does anyone have any suggestions to get this working?