CI update from 1.7 to 2.0 getting Fatal error: Class 'CI_Controller' not found in CodeIgniter.php on line 210

[eluser]tdegryse[/eluser]
I am trying to update CI 1.7 to CI 2.0 and followed the guideline for that (http://ellislab.com/codeigniter/user-gui...e_200.html), for some reason I keep getting following error: Fatal error: Class 'CI_Controller' not found in folders\system\core\CodeIgniter.php on line 210

I copied the website locally and I'm using Easyphp 12.1, the point of the whole thing is to update CI but also make some changes to the website. I really need to get started in the changes. If you need more info, please let me know.

Thanks in advance,
Toon