Phpmailer how to include it to script? - php

Question

I am using PHPmailer github, I use the "gmail.php" from the examples and it works perfect when I open it in my browser. But when I copy the code and add it to my existing signup script I get an 500 Error. Also when I try to include it I get an 500 Error. How can I add phpmailer to my existing signup script?
<?php
/**
* This example shows settings to use when sending via Google's Gmail servers.
*/
//SMTP needs accurate times, and the PHP time zone MUST be set
//This should be done in your php.ini, but this is how to do it if you don't have access to that
date_default_timezone_set('Etc/UTC');
require '../PHPMailerAutoload.php';
//Create a new PHPMailer instance
$mail = new PHPMailer;
//Tell PHPMailer to use SMTP
$mail->isSMTP();
//Enable SMTP debugging
// 0 = off (for production use)
// 1 = client messages
// 2 = client and server messages
$mail->SMTPDebug = 2;
//Ask for HTML-friendly debug output
$mail->Debugoutput = 'html';
//Set the hostname of the mail server
$mail->Host = 'xxxxxx';
// use
// $mail->Host = gethostbyname('smtp.gmail.com');
// if your network does not support SMTP over IPv6
//Set the SMTP port number - 587 for authenticated TLS, a.k.a. RFC4409 SMTP submission
$mail->Port = 587;
//Set the encryption system to use - ssl (deprecated) or tls
$mail->SMTPSecure = 'tls';
//Whether to use SMTP authentication
$mail->SMTPAuth = true;
//Username to use for SMTP authentication - use full email address for gmail
$mail->Username = "xxxxxx";
//Password to use for SMTP authentication
$mail->Password = "xxxxxxxxxxxxx";
//Set who the message is to be sent from
$mail->setFrom('xxx', 'xxx');
//Set an alternative reply-to address
$mail->addReplyTo('xx', 'xx');
//Set who the message is to be sent to
$mail->addAddress('Txxx', 'John Doe');
//Set the subject line
$mail->Subject = 'Welcome to xx!';
//Read an HTML message body from an external file, convert referenced images to embedded,
//convert HTML into a basic plain-text alternative body
$mail->msgHTML(file_get_contents('contents.html'), dirname(__FILE__));
if (!$mail->send()) {
} else {
}