I was getting this error when I click "Add to Cart" everytime, and then I add an HTML Minifier and it seemed to fix it. But now, I get this same error randomly on 1 or more products, but not all, and not all the time. If I wait long enough, eventually it will work for the product(s) in question, but then another product will not add to cart... I do not no where to start or diagnose... I believe that the products will eventually add when the session refreshes, but I am not sure... As to why it is only 1 or a few products at a time and seemingly random... I am completely lost... I love the extension and wish I could use it, but I cannot trust it until I fix this... It is costing me sales and wasting Adwords money... PLEASE HELP!