If you’re using WP e-Commerce to turn your WordPress website into an online shopping cart, you may have ran into a Paypal error that says, “Error Detected, Your shopping cart is empty.”
This can happen when you’re trying to pass a required field like “Name” over to Paypal, but it’s blank. Why would it be blank? Because one of the fields in the Product page that Paypal needs to process the order is empty. It can happen when you start to add variations to an item, but you don’t name the variations.
You need to put in a name in the “Name” field under the “Variations” under each product in the Dashboard. Once you do that, that Name is what is sent to Paypal during the checkout process. It doesn’t work without that.
You can tell which product have variations by looking at the “Stock” category in the Dashboard > Product page. If the variations are turned on, it will show “0~”, other wise it will show “NA”. Once you go in to edit an individual product, you’ll see a “Variations” module. If the “Sizes” is checked, the “Name” field has to be filled in for it to work.
All products with variations need the name field filled in, in order to pass that name to Paypal.
If this doesn’t fix your problem, try one of these references instead: