prob with content & cart modu in the same position

Hi Nicolas, i,ve made a some customization to our site: now the choose product button works in popup window.

The problem is that i have a content module ("productos destacados") and the cart module in the same position:

content module= maintop a
cart= maintop b

checkin the code i noticed something different in the button url, it has "itemid=0", something that the other content modules doesn't have. If i change the module position itemid=0 dissapear, but i don't have any other position to put the cart.

Can you help me?

mercando.algom.co/

PD= the popup is different with that problem, it shows th entire page. In the other module "productos en descuenos" it shows ok, only the product.

somebody?