Leif,
The problem is your store pages are at a different URL from your shopping cart, so cookies will not work. From the ShopSite help docs:
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The mini cart will not work if customers have cookies turned off, or if your store pages and shopping cart are in different domains. In other words, if your store pages are at
www.mydomain.com and the shopping cart is at shop.myhostingprovider.com, the mini cart will not show the items and subtotal in the cart.
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