Change Themplate language

Hi,
i’ve a problem for change language of my template.
I’ve a language folder with corrects .po files as subfolder of my theme folder, but on WordPressAdmin->Setting->General i can change languages using dropdown menu.
I’m able to do it only if i copy entire subfolder into wp-content folder. Now dropdown menu show all languages, but when i change it i don’t see my theme traslated with choose language.

Can someone help me?

Regards