Add to Cart Does Not Work

Just downloaded the Cart 66. Want to add a cart item to my page. When i insert the code. My page becomes completely blank. There are items and content on the page but it disappears. I followed instructions by setting up the prooduct and then inserting code using upload/insert Cart66. Please help.

The coded that does not work is: [add_to_cart item=”SMOO” quantity=”user:1″ text=”add to cart” ajax=”yes” ]

http://wordpress.org/plugins/cart66-lite/