DMS Search error

Fatal error: Call to undefined method DMSHelper::treerecurse() in /public_html/modules/mod_dms_search/helper.php on line 41

I want answers to why this error.

I bought it because it did not work.

Why?????????????????????

on joomla 1.7
$list = DMSHelper::treerecurse(0, '', array(), $children, 9999, 0, 0 );

In helper class no function treerecurse. Why?

on joomla 1.5
$list = JHTML::_('menu.treerecurse', 0, '', array(), $children, 9999, 0, 0 );