report from more than one person that olark code is conflicting with Ajax’ed Shopify Cart Page

I have an upsell I want to offer people from my cart page - it checks if the case is in the cart, and if not, it shows the option to add it - I am using an identical code from my product page and it all shows up fine, but when I click add to cart, only the jquery goes through, and nothing in the cart gets updated - even when i press refresh, nothing has been added to the cart.

Am I missing something?

• go to checkout
• add an amount of item you know not in stock
• click update
• quant doesn't change, but line total gets the right amount.

expected behaviour: quant is filled in with the maximum amount avail
bonus points: message user that this is why we can't add the full quant.

doesn't seem to be working in IE8 or FF3, but it does work in: Safari, Chrome, FF 4.0b, IE6, IE7 and Opera.
(reported by rlanglois)