I have a problem with my store.

I can add a product to the shopping cart when the product has no attributes, but if the product has attributes, it is not possible to click on the 'add to cart' button. (I have sba v4.4 installed using Zen Cart 1.3.7.1, and, as far as I can tell, all the relevant files for the mod are in the correct places)

The button appears to be disabled when the customer wishes to add a product to the cart, and since this seems to be the case only for products with attributes, I am assuming that the problem is related to sba.

I have double-checked everything, as far as I can, but I don't seem to be able to fix the problem - can anyone shed some light on what might be causing this critical phenomenon, PLEASE?