Problem with calendar

Hello everyone.

I’m really a WordPress newbie and I need some help.
I’ve got a website http://www.kopamatakawa.com.pl/ and there is something wrong with calendar what I can’t repair.

http://oi57.tinypic.com/i4plhf.jpg

When I click on “Luty” (February), there should be shown every comics from february, but it shows nothing.

The second problem is calendar dissapears when I click on previous month like this:

http://oi62.tinypic.com/2ilo6dt.jpg

It’s really annoying, because I can’t go to more than one month back.
I want a calendar from this site: http://www.glosywmojejglowie.pl/
I can’t figure it out and I’m sorry if this is really easy to solve, like I said – I’m newbie as hell. I hope someone will help me, there is a link to site, again: http://www.kopamatakawa.com.pl/

Cheers, Mateusz

https://wordpress.org/plugins/comic-easel/