Marketpress out of stock

Hi,
I was wondering, I have buddypress and marketpress installed, do you have to be signed in to shop in the stores?
If you are not signed in, and try to add something to the chart, it says out of stock. I have also tried logging in with a user account, and the same thing happened. It seems it only works when I am logged in as the super admin?
Here is a link
Also if I have added something to the shopping chart as super admin, and then log out, I can then go ahead to paypal to pay!