You would need to include your MY_Controller
class or auto-load it. I suggest you auto-load it by adding the following to your application/config/config.php
file.
function __autoload($class)
{
if (strpos($class, 'CI_') !== 0)
{
if (file_exists($file = APPPATH . 'core/' . $class . EXT))
{
include $file;
}
}
}