[Lionel]

In adminfunctions.php print_delete_confirmation you also need to specify the below (insert it somewhere) or it will switch to default and you will not be able to delete any usergroups. (I don't use prefixes so I have " . ")

case 'usergroup':
$item = $vbulletin->db->query_first("
SELECT usergroupid, title
FROM " . "usergroup
WHERE usergroupid = '" . $vbulletin->db->escape_string($itemid) . "'
");
break;

also in functions.php copy function fetch_query_sql into function fetch_query_sql2 . alter that copy by replacing the 2 instances of " . TABLE_PREFIX . to reflect your master prefix.

Then in usergroup.php call that fetch_query_sql2 instead of fetch_query_sql (many instances)

Now, all that is left is the avatar category that refuses to display. I did do a search and replace for table_prefix avatar so they all have the same.

BTW, there was no problem with userstats and your mod. The problem was with vbadvanced.