Did you give second chance offers to any of your other bidders? Perhaps you want to limit the next auction to only ship to US addresses. Make sure paypal is required and is the only form of payment accepted.
The first auction I held for my 1st gen iPhone was won by some guy that thought it was the 3G despite the auction description being very clear that it was not, very irritating. The second time around the winner was from Australia but actually knew what they bid on and was very prompt with payment and email correspondence. I shipped the iPhone to him, he received it successfully and I ended up $385 richer.