Yojance on "[Plugin: WooCommerce - excelling eCommerce] Checkout Page Not Loading"

I recently installed WooCommerce and besides the "Checkout" page not being created upon installation, there were 2 pages not being selected under Settings->Pages one of them being the Checkout page.

I'm able to list the products and even add them to the cart but when I go to my cart and hit the "Proceed to Checkout" button the pages takes forever to load and finally it throws an Internal Server Error (500).

You can test this by going to:
http://jsainteractive.com/cart?add-to-cart=4872

and then clicking on the Proceed to Checkout button and you'll see it never loads.

- WP: 3.5.1
- WC: 2.0.9
- Payment Gateway: Paypal

Has anyone experienced this error and found a solution for it?

http://wordpress.org/extend/plugins/woocommerce/