Edit vbookie.php and replace
PHP Code:
LEFT JOIN " . TABLE_PREFIX . "thread AS thread ON thread.vbookie_item_id = item.item_id
with
PHP Code:
LEFT JOIN " . TABLE_PREFIX . "thread AS thread ON (thread.threadid = item.threadid)
[sql]ALTER TABLE vbookie_items ADD INDEX (item_status);
UPDATE vbookie_items, thread SET vbookie_items.threadid=thread.threadid WHERE thread.vbookie_item_id=vbookie_items.item_id;
[/sql]
Execute these queries and check if it does help.