Hi,
on a certain ammount of my articles an error is displayed at the bottom of the page and site desing as well as letters are messed up. The error i'm getting is:

Warning: Invalid argument supplied for foreach() in /home/rabdanas/public_html/components/com_k2/templates/default/item.php on line 603

Fatal error: Call to a member function getPagesLinks() on a non-object in /home/rabdanas/public_html/components/com_k2/templates/default/item.php on line 660

It completely destroys the site. Im running a 2.6.9 version. Everything is up to date. On the recent articles there is no problem, and they display properly. After a while they stop functioning and turn to this...

www.rabdanas.com/index.php/kultura/item/59-zasto-su-svi-u-sarengradu
or
www.rabdanas.com/index.php/vijesti/item/84-odrzana-treca-sjednica-skupstine-tzg-raba

Unable to detect problem, please help.

Ok, i managed to narrow the problem search.

If i disable the facebook comments in k2 properties (preferences > comments > disable), the problem goes away and article is displayed properly. But the fb comments section is important so i wish to keep it. Any idea?

Which extension are you using for FB comments?
By default K2 does not provide integration with FB's comments.

I am using BT social share

Since this issue is caused by that extension, you need to address this issue to the BT devs.