Fatal error DB since 2.0.0

[eluser]-Menno-[/eluser]
Dear readers,

I've recently upgraded my systems to CI 2.0.0.
Too bad this upgrade responded with global errors in my project.

Fatal error: Call to undefined method CI_DB_mysql_driver:elect()

This error keeps coming up, it seems it has nothing to do with my specific method, because it turns up on multiple webpages.
An example of my code is this one:
$query = $this->db->select('name')->get('language');

Nothing fancy about it, it has always worked perfectly fine. Until 2.0.0.
Just to prevent this question, yes, Active Record is turned on:

(...)
$active_group = "default";
$active_record = TRUE;

$db['default']['hostname'] = "localhost";
(...)

Maybe I've missed something in the releasenotes, or the forum, for that matter. Hopefully I've just forgotten something, thanks for the help in advance!

[eluser]marceloabelda[/eluser]
I have the same error.
Let me know if you could fix it.

[eluser]n0xie[/eluser]
Did you autoload the database class?

[eluser]-Menno-[/eluser]
Yes, Database and Session are currently in the array of autoload libraries.
As I posted, it only occurs since 2.0.0. When I restore a back-up from 1.7.3, it works again.
This doesn't mean I want to keep working in 1.7.3.

Hopefully someone else has had this problem too and knows how to repair it?

[eluser]n0xie[/eluser]
Does your model extend CI_Model and do your controllers extend CI_Controller? Did you change your constructors?

[eluser]marceloabelda[/eluser]
In a clean install, no similar errors (tested) with database, select, etc.
But i have: HMVC, MY_Controller and MY_Modules extending CI_Controllers or CI_Modules. Then the problem occurs, in my case.
I keep trying.

[eluser]InsiteFX[/eluser]
Make sure if you are upgrading that you also copy the new index.php file over!

InsiteFX

[eluser]marceloabelda[/eluser]
following
the error occurs in MY_Model extends CI_Model
...
$this->load->library('firephp');
..
error:
Fatal error: Call to a member function library() on a non-object in
(firephp, database, etc..)

on the other hand, in MY_Controller extends CI_Controller
...
$this->load->library('firephp');
..
NO ERRORS
Im using hmvc