Hi,
Tables should be deleted in specific order.
try with item_resources, item_description, item_comment, item_stats, category_description, ....
Try to delete them one by one, if it can not be deleted, don't worry, keep trying with other tables, once all possible tables are deleted, repeat the process.
This is because some tables depends on other. For example, t_item_description needs t_item and t_locale , so you can not delete t_item or t_locale first...