Repeating posts

I installed the plugin, and it worked fine at first, but now I have the following problem: when I scroll to the last page of posts, this page keeps repeating over and over. You can see what I mean if you try scrolling down on this page: http://www.pretproduse.ro/categorie/reduceri-si-promotii-2/reduceri-ceasuri/.

The weird thing is that this the plugin works fine on some categories. For example, on the following page http://www.pretproduse.ro/categorie/food/catering/, when you scroll down to the last post, it simply stops.

I mention that I use a custom theme, and wordpress 3.5.2 (I upgraded recently from 3.5.1, but that didn’t solve the problem)

I hope you can help me find the cause of this behavior.

Thank you in advance,
Alex