He's saying that he sold gold to a buyer, and the buyer has posted a dispute/claim on the money.
d0n, its very simple. Reply to the dispute stating the purchase was for Ingame-Virtual Currency, intangible goods, and you delivered, and the buyer does not fall under paypal buyers protection.
Try this, and easy way, just be calm, research into how to react, keep civil and make yourself look like the good guy.