Tree behavior does not work!!!

Hi, everyone. This is second time to post with this kind of content to this group. My first time post was gone, never appears, and dunno why, so I m writing the post again.  I just used Tree behavior for category, according to what cakePHP manual said. But when I used generatetreelist(), it all  times says following:  Warning (512): SQL Error: 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 'generatetreelist' at line 1 [CORE\cake\libs \model\datasources\dbo_source.php, line 684] ... $sql	=	"generatetreelist" $error	=	"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 'generatetreelist' at line 1" $out	=	null ... msController::category() - APP\controllers\items_controller.php, line 12 ... Query: generatetreelist  I found that the system actually does not recorgnize what generatetreelist() is, but do not know what to do...  I created table called lkp_itemcate with following fields: id, parent_id, lft, rght, name, img_url, level, created, modified  And made Model class following: class Itemcate extends AppModel { 	var $name = 'Itemcate'; 	var $tablePrefix = 'lkp_'; 	var $useTable = 'itemcate';  	var $actAs = array('Tree'); }  and then used generatetreelist() in controller:  class ItemsController extends AppController { 	var $name = 'Items'; 	var $modelClass = 'Itemcate'; 	var $uses = array('Itemcate');  	function category($act = 'index', $id = null) { 		... 		$list = $this->Itemcate->generatetreelist(null, null, null, '   ');                 ...         }         ... }  Please help me to settle with this issue. I really can not find what s wrong, googled for 2 hours, but never find such a case like mine. Best regards, Raymond.