[Chris M]

Ah I've figured out why

For some reason the plugin I downloaded had:

<plugins>
	<plugin active="1" devkey="show_description_on_showg" product="vbulletin">
		<title>Show Description On Showgroups - Usergroup Loop</title>
		<hookname>showgroups_user</hookname>
		<phpcode>if (isset($locationfieldselect2)) {
	$locationfieldselect = $locationfieldselect2;
}
unset($locationfieldselect2);</phpcode>
	</plugin>

That should be:

<plugins>
	<plugin active="1" devkey="show_description_on_showg" product="vbulletin">
		<title>Show Description On Showgroups - Usergroup Loop</title>
		<hookname>showgroups_user</hookname>
		<phpcode><![CDATA[if (isset($locationfieldselect2)) {
	$locationfieldselect = $locationfieldselect2;
}
unset($locationfieldselect2);]]></phpcode>
	</plugin>

Satan