In file install.class.php, row 1636 contains this SQL statement
$this->updateQuery('UPDATE #__acym_rule SETordering= (SELECT MAX(ordering) + 1 FROM #__acym_rule) WHEREid= 17');
In MYSQL you can't modify the same table you use in the select statement. I guess you can use an update statement similar to this one:
UPDATE #__acym_rule
SET `ordering` = (SELECT * FROM (SELECT MAX(`ordering`) + 1 FROM #__acym_rule) AS sub)
WHERE `id` = 17
