Pagenavi doeasn't work anymore

I installed this and its works fine but from few days there is a problem with options page. When i put something it dissapear. It ca’t save any options so pagenavi doesn’t view on my site.
What is the problem?

Yes, field in the options menu are empty :/
Any idea?
Site: http://www.strefawalkingdead.pl/

http://wordpress.org/extend/plugins/wp-pagenavi/