Try this:
For guests and banned (who cares what they see?), if it shows that error again, maybe Template Conditionals (the one I use) and PHP In Templates works different.
<if in_array($GLOBALS['mybb']->user['usergroup'], array(1,7)) then>
// code for guests
</if>
For guests and banned (who cares what they see?), if it shows that error again, maybe Template Conditionals (the one I use) and PHP In Templates works different.