Jim,
there are many post office ‘black holes’ in Europe, Africa and Asia. Best suggestion is if in doubt then exclude from your countries that you sell to (or buy from). I would not sell to Indonesia, China, India, ex-Eastern bloc countries and Italy. Unfortunately, hard times brings out the worst in people and the operative word is ‘scam’. I will not deal with Germany, simply because of the language difficulties and the Germans only accept bank drafts or cash (Euros), not PayPal.
In my several thousand eBay purchasing transactions (99% in the States), I must state that there are scammers on the continental United States, as well and eBay and PayPal are unable/reluctant to pursue them, particularly if they are eBay 'power sellers' or eBay storefront sellers. It seems that the more feedback a power seller or storefront seller has, then the more credibility that they have with eBay, regardless of the hundreds of negative feedback they have received. EBay's protection policies are merely paper tigers. Predominantly though, the American sellers are extremely friendly and helpful and I would deal with them again and again.