[SimonP]

Here is the auto-ban-fix f?r 3.6.x boards:

In file WARN.PHP search for this:

foreach ($vbulletin->usergroupcache AS $usergroupid => $usergroup)
		{
			if ($usergroup['genericoptions'] & $vbulletin->bf_ugp_genericoptions['isbannedgroup'])
			{
				if ($vbulletin->options['warn_ban_usergroup'] == $usergroupid)
				{
					$Found = $usergroupid;
				}

				$Temp = $usergroupid;
			}
		}

Replace all lines above with one line:

$Found=$vbulletin->options['warn_ban_usergroup'];

This removes the autosearch-for-ban-group feature that was failing in 3.6.x boards,

Also make sure that you have the set the correct Banned Usergroup-ID in AdminCP -> vBulletin Options -> Inferno Warning Options.