Big Problems using Marketpress 2.4.2

Hi WPMU Devers!

Well after that calm start may I say HHHHHHEEEEEELLLLLPPPP! hehe

Right ok Ive installed Marketpress 2.4.2 on WP single install 3.2.1. Im running a theme Ive never worked with before called Soundcheck. My problems may be a theme issue but I could really use some help.

So the issues are:

1. products are not displayed on the default "products" page (I can get them to display on a custom page, which you will see in the menu and on the root /store/ page).
2. products are not added to cart or perhaps they are but just not displayed in the cart page.
3. when I try to add "Walking Home Downloadable Album" to the cart I get a strange error: "Sorry, there is a per order limit of 1 for.." What does this mean and why is it happening.

Here is the link: http://www.johnmontgomerysongs.com

Im really struggling and need this to be working yesterday! Like I said any help greatfully received.

Ta