Database Error

If  some one unregister I get   database error

Query:

SELECT `cmt_id`, `cmt_parent_id` FROM [db_prefix]_cmts WHERE `cmt_author_id` = '896' AND `cmt_replies` = 0

Hello [db_prefix] should be replaced with real db table!

in '/home/homepages/apps/dolphin-7.0.1/inc/classes/BxDolCmtsQuery.php' at line 167.

there is

$a = $this->getAll ("SELECT `cmt_id`, `cmt_parent_id` FROM {$this->_sTable} WHERE `cmt_author_id` = '$iAuthorId' AND `cmt_replies` = 0");

So where should I replace this?

Thank you very much!