For starters, you need to change that link on GamblerTillIDie.com to not include the zenid in it ...

That will cause a lot of problems ...

I am not sure about the confusion issue ... as it took me right to the product and there is the Add to Cart ...

Then adding to the cart the checkout link is there ...

They are then taken to login/create account and continue to checkout ...

It is pretty straight forward ... I think ... the way you have it set up ...