Controllershippingflat' not found... on line 39

Hello.
I need help.
I use Opencart 1.5.5.1 with Slovenian language pack.

I tried to rename "Flate rate" into my language (extension/shipping/flat rate) in ftp client (Cyberduck).
When i did it for the first time it worked fine. But then i changed my mind and try to rename it again into simalar name...
And when i did it i get this error when i try to manage Flat rate:
Fatal error: Class 'Controllershippingflat' not found in /domains/profoto.si/public_html/system/engine/front.php on line 39
If i try to remove flate rate i get this:
Fatal error: Class 'ControllerShippingflat' not found in /domains/profoto.si/public_html/admin/controller/extension/shipping.php on line 155

I dont know what to do.
Can i overwrite Opencart not loosing data in my webstore?
I tried to overwrite flat.php and shipping.php from original opencart file several time but no success.

Thank you for your time.
Regards
Peter

Ensure you are modifying the language, and the the controllers