[Boofo]

Try replacing this:

if ($vbulletin->options['sound_notification_enabled'])
{
	$templater = vB_Template::Create('soundnotification');
	$soundnotification .= $templater->render();
	vB_Template::preRegister('header',array('soundnotification' => $soundnotification));
}

With his:

if ($vbulletin->options['sound_notification_enabled'])
{
	$templater = vB_Template::Create('soundnotification');
	$template_hook['header_userinfo'] .= $templater->render();
}