Odd. It's some kind of strange problem with the permalinks, because this works: http://mantasgarnelis.com/lpsk/?s=moter%C5%B3+centras&paged=2 or http://mantasgarnelis.com/lpsk/?s=moter%C5%B3+centras&paged=3 and so on.
I don't know what's causing the problem here, but changing from the pretty permalink to the paged parameter seems like a solution.