cart no load in front page modules

[marceff]

I am using Joomla 2.5.14 + VM 2.0.26d + PHP 5.3.10.
I have purchased products presenter and product slideshow modules and enabled "add to cart" button but when selecting no product is loaded into cart. I have tried to uncheck ajax with no result, I've also disable JQuery with same result. Apparently not js conflict is on (according to debugger).
By selecting "add to cart" no popup is showed (although the option is checked) and the page stay the same but at the end it shows the cart (the two bars with in the middle the message "no products in the cart" and "continue shopping").
Is anybody ever experienced the same issue?