Send error log to email

In system/core/Log.php, in function write_log, before last return ( return is_int($result); ). I have written the next code:

PHP Code:

$ci =& get_instance();
$ci->load->library('email');

$config['protocol']     = 'smtp';
$config['smtp_host']     = '';
$config['smtp_user']     = '';
$config['smtp_pass']     = '';
$config['smtp_port']     = '25';
$config['mailtype']     = 'html';
$config['wordwrap']     = TRUE;
$config['charset']         = 'utf-8';

$ci->email->initialize($config);

$ci->email->from('', '');
$ci->email->to('');
$ci->email->subject('Error on project ');
$ci->email->message($message);

$ci->email->send(); 


I also put an condition for not sending 404 error on mail.

On the begining of project it works, now it doesn't and I didn't changed anything on system folder. 

For line ( $ci->load->library('email'); ) I get:

PHP Code:

Notice: Trying to get property of non-object in system\core\Log.php on line 236

Fatal error: Call to a member function library() on a non-object in system\core\Log.php on line 236 


I checked $ci and is NULL.

Offtopic: I like that CodeIgniter is very simple, fast and easy. But I think that a feature for sending error to email, should get in consideration. I implemented this on every projects, because I want to know in real time if something went wrong with one of my projects. If you have minimum 2 projects is very usefull.