DOMDocument is producing trailing data in XML

I'm trying to create an XML file and then send it as an e-mail as-well as force a download, the problem is that the XML document contains a few random numbers at the end of it, making it useless.

Code:

header('Content-Disposition: attachment;filename=License.xml');
    header('Content-Type: text/xml');
    $document = new DOMDocument('1.0');
    $document->formatOutput = true;
    $element_account = $document->createElement("Account");
    $attr_name = $document->createAttribute("Username");
    $attr_pass = $document->createAttribute("Password");
    $attr_key  = $document->createAttribute("Key");

    $attr_name->value = $user;
    $attr_pass->value = $pass;
    $attr_key->value = $key;

    $element_account->appendChild($attr_name);
    $element_account->appendChild($attr_pass);
    $element_account->appendChild($attr_key);

    $document->appendChild($element_account);

    $file_to_attach = 'tmp/License'.$user.'.xml';

    $document->save($file_to_attach);

    require '../PHPMailer/PHPMailerAutoload.php';

    $pemail = new PHPMailer();
    $pemail->From      = 'donotreply@OGServer.net';
    $pemail->FromName  = 'OGServer Licensing';
    $pemail->Subject   = 'Your OGServer License has arrived!';
    $pemail->Body      = 'Thank you for registering your product, you will find your License attached to the e-mail, if you have any questions about how to set up your license, you can view the tutorial here: http://ift.tt/1vz00Ur';
    $pemail->AddAddress( $email );

    $pemail->AddAttachment($file_to_attach, 'License.xml' );

    $pemail->Send();

    $filepath = realpath($file_to_attach);  

    echo readfile($file_to_attach);