Problem with replicating a featured products module in PS 1.3.x

[damnated]

Hello, I'm working on a module, that would display the featured products in a slide, every slide would look like a column in the featured products block, with the picture, view button and add to cart button.

Now, I copied most of the content of the featured products block, and everything works, except the adding to the cart part. The button points to the same location.

cart.php?qty=1&id_product=6&token=65aaf285a020d46e26ac636faec8057a&add;

For instance. When I click on it, the product gets added to the cart, (if I refresh the page, the cart is updated) but the cart is not getting updated, the animation is not being displayed etc. I even get a javascript error,

elementToTransfert is null

on blockcart/ajax-cart.js Line: 174.

It seems that the js script is not receiving the product id from the cart.php script (that receives it, because it adds it to the cart), but I have no idea how to solve this, because I haven't changed anything in the blockcart module.

Any ideas?

PS: the same module works just great on prestashop 1.4, but unfortunately I have to install this on an older shop as well.