Cannot Get Past Registration Information Screen with Multiple Quantities of a Single Product

I have a site for a youth football organization. I thought I had everything up and running correctly, but I am having the following issue. Let's say somebody puts a quantity of (1) Football Registration in their shopping cart and then clicks on checkout, everything is fine and works as advertised. If they put a quantity of (2) of any single registration product in their shopping cart and then click on Checkout they will get the appropriate number of forms to fill out. When they click on continue from this screen, they get the following error: "You cannot register yourself for the same item more than once". I have "Allow Multiple registrations" checked in the registration type field and can't figure out how to make this work. This is critical to get working because I went live with the site not knowing this issue existed and we are getting all kinds of calls from parents wanting to sign up 2 different boys to play football. If you would like to look at the site, it is http://register.cyfa.org