CLICK CALCULATE BUTTON on CHECKOUT broke?

[ehdesign]

HEre is my URL:

http://www.buyrog.com/new/

When I add something to the cart and go to checkout, I try to click on the CALCULATE button to update the quantities, but I get an error that a product cannot be added to the cart.

Can some one take a look and see me any feedback that they can think of?

Thanks.

[ehdesign]

SOLVED - it was my own bad JS. Thanks.

[charmedbytina2]

I was able to add a product to the cart, remove it using the calculate button, then I was able to change the quantity in the cart using the calculate button.

I did not progess to checkout since I do not want to create an account.

Tina