Thanks for the response. No, we are not using the stock limitations. The issue is not the stock numbers. The problem is with product attributes. For example, the product may come in many sizes and colors. Using Product Attributes, we give the ability to the customer to choose a color or size. These choices are added to the order, per item.
These choices are displayed properly in the shopping cart and on the checkout order summary before it goes to paypal. BUT once the transaction returns from Paypal, we lose all of the attribute choices. The result is we have no idea what size or color product to send to the customer, as it does not show up on the order.
I'm starting to wonder if Paypal is even worth the trouble...