Call to a member function real_escape_string() on a non-object

I have the same problem although i have the autoinit set.
I needed to do this inside the

C:\work\Codefi UI\codeigniter\system\database\drivers\mysqli\mysqli_driver.php

to make the error go away.

Code:

// --------------------------------------------------------------------

/**
* Platform-dependant string escape
*
* @param    string
* @return    string
*/
protected function _escape_str($str)
{
    if($this->conn_id)
    {
        return $this->conn_id->real_escape_string($str);
    }
}

DO NOT DO THIS! You're making yourself vulnerable to SQL injections!

What do you suggest? I got the same problem