Empty page when use escape_string

[eluser]Hamed[/eluser]
Hello,
When I add escape_string to my code I get empty page:

Code:

$username = $this->db->escape_string($this->input->post('username'));
        $password = $this->db->escape_string($this->input->post('password'));

[eluser]CroNiX[/eluser]
You probably have errors/debug mode turned off, and there is no "escape_string" method.
http://ellislab.com/codeigniter/user-gui...eries.html