My Problemcode

<?php


// no direct access
// defined( '_JEXEC' ) or die( 'Restricted access' );

class modGoogleAnalyticsHelper
{
	var $_trackingCode = '';
	var $_virtalPageEnabled = false;
	var $_domainName = '';
	
	function setTrackingCode ( $value )
	{		
		$this->_trackingCode = $value;
	}
	
	function getTrackingCode ()
	{
		return $this->_trackingCode;
	}

	function setVirtualPageEnabled ( $value )
	{
		$this->_virtualPageEnabled = $value;
	}
	
	function getVirtualPageEnabled ()
	{
		return $this->_virtualPageEnabled;
	}
	
	function setDomainName ( $value )
	{
		$this->_domainname = $value;
	}
	
	function getDomainName ()
	{
		return $this->_domainname;
	}

	/**
	*  Get Parameter from Joomla System
	*/
	function getParamsFromSystem ( $params )
	{		
		$trackingCode = $params->get('trackingcode');		
		$domainName = $params->get('domainname');				
		$virtualPage = $params->get('virtualpage');	
		
		$this->setTrackingCode ( $trackingCode );
		$this->setDomainName($domainName);
		$this->setVirtualPageEnabled($virtualPage);
		
		return 1;
	}
	  
	  
    /**
     * Retrieves the hello message
     *
     * @param array $params An object containing the module parameters
     * @access public
     */    
    function getAnalyticsCode( $params )
    {
        return '</b>Hello, World - Alex</b>';
    }
}

?>


Fatal error: Call to undefined method JDocumentRendererModule::setTrackingCode() in /var/www/html/modules/mod_googleanalytics/mod_googleanalytics.helper.php on line 63