Hi I download JA Dinner template, and something happen, I dont know if its something with my server or the template, but when I install the quickstart and wait one day... something happen with my index.php, someting add this code... and my website breaks, what can I do? to prevent this? I change index.php permissions to only read, but happen again, the index.php is the one inside template/index.php

the code is:
<?php
/**
------------------------------------------------------------------------------
@package T3 Framework for Joomla!
------------------------------------------------------------------------------
@copyright Copyright (C) 2004-2013 JoomlArt.com. All Rights Reserved.
@license GNU General Public License version 2 or later; see LICENSE.txt
@authors JoomlArt, JoomlaBamboo, (contribute to this project at github
& Google group to become co-author)
@Google group: https://groups.google.com/forum/#!forum/t3fw
@Link: http://t3-framework.org
------------------------------------------------------------------------------
*/

// no direct access
defined('_JEXEC') or die;

//check if t3 plugin is existed
if (!defined('T3')) {
if (JError::$legacy) {
JError::setErrorHandling(E_ERROR, 'die');
JError::raiseError(500, JText::('T3_MISSING_T3_PLUGIN'));
exit;
} else {
throw new Exception(JText::('T3_MISSING_T3_PLUGIN'), 500);
}
}

$t3app = T3::getApp($this);

// get configured layout
$layout = $t3app->getLayout();

$t3app->loadLayout($layout);

THIS DOESNT BELONGS TO INDEX.PHP??