cron command doesn't work in contropanel

[eluser]yusuf[/eluser]
misplacedme,

Thanks for your reply. corn was used for backup, remainder etc

backup script is

function backup()
{
// Set memory_limit to -1 so we won't get errors.
ini_set('memory_limit', '120m');
ini_set('display_errors',1);
error_reporting(E_STRICT);

$this->load->dbutil();
$backup =& $this->dbutil->backup();

// Load the file helper and write the file to your server
$this->load->helper('file');
var_dump(write_file('backups/dbbak' . date('Y-m-d') . '.gz', $backup));

// Load the download helper and send the file to your desktop
$this->load->helper('download');
}

is there any error please reply me