Virtuemart cart always empty, does not add products.

[krikesa]

Joomla Version: 2.5.28
VirtueMart 2.6.16
link: www.medo-stil.hr
It is in Croatian, so here is direct link on one of the products:
http://www.medo-stil.hr/web/index.php/katalozi-dijelova/za-quad-atv/zongshen-200cc-zracno-hladenje/dihtung-auspuha-detail

When I hit add to cart (dodaj u košaricu) popup appears, and when I go show cart (prikaži košaricu) then there is no products inside.

I had some problems before with search, and I installed easy jquery and it worked. I was not administrator of this site, so I do not know what owner did on it exactly.

I tried to disable virtuemart jquery at VM->configuration> templates

I tried to disable modules and plugins, but havent found conflicting module or plugin.

Tried many suggestions on the forums, but nothing helped.

I must admit that I am not expert, nearly novice, but my friend is begging me to help him with this for some time now.

[GJC Web Design]

can see no JS errors etc - can only suggest you try with the standard Beez template to see if the template has a problem

[krikesa]

I tried beez as well. Up until today, it was some other template active and today I switched to this Rockettheme.
EDIT: just to avoid confusion, it is same situation with all templates