That means that an Auction lot whose status is "Online" does not have an Auction id number in the Auction id number field. Now either, you have accidentally changed the status of an Auction lot to "Online". Or when you listed, eBay did not return an Auction id number. That happens sometimes.
Click the Download Auction id and let AW2000 work. If you have already closed that dialog box, you can still download the Auction id number(s) by going to Auction Site | Download Auction id's. And letting AW2000 work.
Does that help?
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