You are not the only one. It happened to me too. eBay system is telling you to select or type label to use for the posting. On the right side of your message you will see "Labels" and below it you will see "Choose a Label:"  You need to select the appropriate label for the message you are posting. Examples are Fees, Shop, VAT, Return, Selling tools, Technical issues, etc. That's all. eBay has a funny way of explaining its self. I hope this helps.