SQL-запрос:

-- -- Дамп данных таблицы `bb_bt_dlstatus_mrg` -- INSERT INTO `bb_bt_dlstatus_mrg` (`user_id`, `topic_id`, `user_status`, `last_modified_dlstatus`) VALUES (3, 184, -1, '2011-01-17 05:11:52'), (18, 143, -1, '2011-01-17 05:11:52'), (30, 184, 0, '2011-01-17 05:11:52'), (38, 253, 0, '2011-01-18 05:16:09'), (3, 266, -1, '2011-01-18 05:16:09'), (5, 158, -1, '2011-01-19 05:05:03'), (49, 158, 0, '2011-01-19 05:05:03'), (19, 335, -1, '2011-01-19 05:05:03'), (46, 335, 1, '2011-01-19 05:05:03'), (42, 414, -1, '2011-01-23 05:28:46'), (44, 328, 1, '2011-01-20 05:05:22'), (6, 328, -1, '2011-01-20 05:05:22'), (34, 216, -1, '2011-01-21 10:11:18'), (12, 253, 1, '2011-01-20 05:05:22'), (44, 378, 1, '2011-01-24 05:07:28'), (44, 253, 0, '2011-01-20 05:05:22'), (6, 319, -1, '2011-01-21 10:11:18'), (48, 369, -1, '2011-01-20 05:05:22'), (37, 369, 1, '2011-01-20 05:05:22'), (46, 319, 1, '2011-01-21 10:11:18'), (44, 384, 1, '2011-01-20 05:05:22'), (6, 379, -1, '2011-01-20 05:05:22'), (56, 3[...]

Ответ MySQL: Документация
#1168 - Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exist

--
-- Структура таблицы `bb_bt_dlstatus_mrg`
--
CREATE TABLE IF NOT EXISTS `bb_bt_dlstatus_mrg` (
`user_id` mediumint(9) NOT NULL default '0',
`topic_id` mediumint(8) unsigned NOT NULL default '0',
`user_status` tinyint(1) NOT NULL default '0',
`last_modified_dlstatus` timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP,
KEY `user_topic` (`user_id`,`topic_id`),
KEY `topic_id` (`topic_id`)
) ENGINE=MRG_MyISAM DEFAULT CHARSET=utf8 UNION=(`bb_bt_dlstatus_main`,`bb_bt_dlstatus_new`);

) ENGINE=MRG_MyISAM DEFAULT CHARSET=utf8 UNION=(`bb_bt_dlstatus_main`,`bb_bt_dlstatus_new`);

) ENGINE=MyISAM DEFAULT CHARSET=utf8 UNION=(`bb_bt_dlstatus_main`,`bb_bt_dlstatus_new`);