It appears that you were trying to work on a Polish translation of the wiki's Main Page. I don't think you were aware of the fact that you were changing the English version of the page, which is a highly visible page, and thus really needs to stay in English. I have reversed your changes; please avoid making any changes to the English page in the future.
I see that you have made a copy of that page on your User page. That's good. That will be a much better place for you to work on your translation efforts. When you are done, I'd be happy to help you get it placed in the proper place on the wiki. You may want to review the Translation page to help you understand the official procedure for translating wiki pages. -- Aebrown 15:25, 17 October 2011 (UTC)