I don't get it, I get this message almost everytime... "Unfortunately, access to this particular item has been blocked due to legal restrictions in some countries. We are blocking your viewing in an effort to prevent restricted items from being displayed. Regrettably, in some cases, we may prevent users from accessing items that are not within the scope of said restrictions because of limitations of existing technology. Please accept our apologies for any inconvenience this may cause, and we hope you may find other items of interest on eBay.".
If you see it, I also should... 
Here is your fix, the issue is Firefox and too many languages installed on the browser...
This is because eBay stupidly assumes that if your browser claims you might speak German (or French, I believe), you must be in a country where viewing such items is illegal.
Specifically, the work-around is to remove any languages that you don't speak from the list of languages in the "Language" tab of the International pane of the System Preferences.
If you do speak German or French or whatever the blocked language du jour is, you'll have to remove it, too, to make the eBay nonsense work, but for most Camino users, simply removing other languages is sufficient.