执行SQL页面报错

08:31:46 ERROR: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; 
check the manual that corresponds to your MySQL server version for the right syntax to use near 'wHeRe id = '136'' at line 1<p>
The sql is: 
UPDATE `zt_task` SET `assignedTo` = 'closed', `assignedDate`=？ wHeRe id = '136'</p> in D:\ZenTaoPm\xampp\zentao\lib\base\dao\dao.class.php on line 1392, last called by D:\ZenTaoPm\xampp\zentao\lib\base\dao\dao.class.php on line 766 through function sqlError.
in D:\ZenTaoPm\xampp\zentao\framework\base\router.class.php on line 2196 when visiting /zentao/upgrade.php?m=upgrade&f=execute