Hey Witold,

I am really sorry for the delay of this reply as we are currently having a Joomla conference here in Malaysia and most of the team are involved in the preparation.

It seems like hitting this error ->

Notice: Undefined property: EasyBlogPost::$introtext in /home/wesolalahl/www/wesolalapka/wesolalapka.pl/plugins/content/easydiscuss/easydiscuss.php on line 582

I already applied some fix in this file, it should work fine now.
/Joomlafolder/plugins/content/easydiscuss/easydiscuss.php

Can you give it a try now?