[derfelix]

shouldnt you also register post variable in your template?

$arp_var = "{vb:raw thread.title}";

$templater = vB_Template::create('ARP_TEMPLATE');
$templater->register('arp_var', $arp_var);
$templater->register('post', $post);
$template_hook["postbit_end"] .= $templater->render();

just a thought..
F.