Payplans Donation Module gives the following error in popup
An error has occured
<strong>AJAX Loading Error</strong><br/>HTTP Status: 500 (Internal Server Error)<br/>Internal status: error<br/>XHR ReadyState: 4<br/>Raw server response:<br/><!DOCTYPE html>
<html lang="en-GB" dir="ltr">
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta charset="utf-8" />
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>0 Call to a member function _autoRegister() on null</title>
<link rel="stylesheet" href="/media/gantry5/assets/css/font-awesome.min.css?5c140c0f" type="text/css" />
<link rel="stylesheet" href="/media/gantry5/engines/nucleus/css-compiled/nucleus.css?5c140c10" type="text/css" />
<link rel="stylesheet" href="/templates/rt_isotope/custom/css-compiled/isotope__error.css?5c140c40" type="text/css" />
<link rel="stylesheet" href="/templates/rt_isotope/custom/css-compiled/isotope-joomla__error.css?5c140c40" type="text/css" />
<link rel="stylesheet" href="/templates/rt_isotope/custom/css-compiled/custom__error.css?5c140c40" type="text/css" />
<script type="text/javascript" src="/media/jui/js/jquery.min.js"></script>
<script type="text/javascript" src="/media/jui/js/jquery-noconflict.js"></script>
<script type="text/javascript" src="/media/jui/js/jquery-migrate.min.js"></script>
<script type="text/javascript" src="/media/jui/js/jquery.ui.core.min.js"></script>
<script type="text/javascript" src="/media/jui/js/jquery.ui.sortable.min.js"></script>
<script type="text/javascript" src="/media/jui/js/bootstrap.min.js"></script>
<script type="text/javascript" src="/media/system/js/mootools-core.js"></script>
<script type="text/javascript" src="/media/system/js/core.js"></script>
<script type="text/javascript" src="/media/system/js/mootools-more.js"></script>
<script type="text/javascript" src="/
An error has occured
<strong>AJAX Loading Error</strong><br/>HTTP Status: 500 (Internal Server Error)<br/>Internal status: error<br/>XHR ReadyState: 4<br/>Raw server response:<br/><!DOCTYPE html>
<html lang="en-GB" dir="ltr">
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta charset="utf-8" />
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>0 Call to a member function _autoRegister() on null</title>
<link rel="stylesheet" href="/media/gantry5/assets/css/font-awesome.min.css?5c140c0f" type="text/css" />
<link rel="stylesheet" href="/media/gantry5/engines/nucleus/css-compiled/nucleus.css?5c140c10" type="text/css" />
<link rel="stylesheet" href="/templates/rt_isotope/custom/css-compiled/isotope__error.css?5c140c40" type="text/css" />
<link rel="stylesheet" href="/templates/rt_isotope/custom/css-compiled/isotope-joomla__error.css?5c140c40" type="text/css" />
<link rel="stylesheet" href="/templates/rt_isotope/custom/css-compiled/custom__error.css?5c140c40" type="text/css" />
<script type="text/javascript" src="/media/jui/js/jquery.min.js"></script>
<script type="text/javascript" src="/media/jui/js/jquery-noconflict.js"></script>
<script type="text/javascript" src="/media/jui/js/jquery-migrate.min.js"></script>
<script type="text/javascript" src="/media/jui/js/jquery.ui.core.min.js"></script>
<script type="text/javascript" src="/media/jui/js/jquery.ui.sortable.min.js"></script>
<script type="text/javascript" src="/media/jui/js/bootstrap.min.js"></script>
<script type="text/javascript" src="/media/system/js/mootools-core.js"></script>
<script type="text/javascript" src="/media/system/js/core.js"></script>
<script type="text/javascript" src="/media/system/js/mootools-more.js"></script>
<script type="text/javascript" src="/