[WP eCommerce] No "View Your Cart" button

I’ve been trying to work with the ecommerce plugin for weeks now, and have given up trying to figure it out myself.

I have a “checkout” page, which previously allowed people to view whats in their cart before checking out, but suddenly it has stopped working. When you click on the “view your cart” link it tells you that your cart is empty. If you click on the title “Checkout” however right above that, it takes your to your actual cart-page on a completely separate page named “?page_id=388”. I can’t exactly link to that, or have it forward (since the “checkout” page has some sticker on it telling me not to touch it).

If anyone would like to see how things work and tell me what I’m doing wrong:
http://knightfallgames.com/store-cat/
is the main store page. You can go among the categories and add test-products, then either go back to the store link to view your cart, or click on a product link “add to cart” button which seems to work for some reason.

My basic question: Is there a way to have an actual “View Your Cart” button on the page anywhere?

Did the guy who installed and messed with the WP before me mess it up really badly?