SMF install problem with Call to undefined method synccache::getFullTableName()

PHP Fatal error: Call to undefined method synccache::getFullTableName() in D:\webs\mySite\manager\processors\cache_sync.class.processor.php on line 101 

global $modx;

		$tmpPHP = "<?php\n";

		// SETTINGS & DOCUMENT LISTINGS CACHE

		// get settings
		$sql = 'SELECT * FROM '.$modx->getFullTableName('system_settings');

// initiate a new document parser
include_once('../manager/includes/document.parser.class.inc.php');
$modx = new DocumentParser;