The theme since I am using WordPress in Slovenian language and the theme also goes to use that, but the translation is wrong. I think you have mixed up Slovenian language with Slovakian language, which is not hard to do. It is hard to understand since there is a Slovakian translation already, that nobody noticed that the languages are the same.
Hope this get resolved,
PS: using WordPress 3.8-sl_Sl and Graphene 1.9.2