That error actually informs you that the software is not available at all. I've used a Mac and changed to various countries including the US and the message is the same, then I decided to find the official website and I did find it, but the problem is now related to its availability. The software and the websites appear to be discontinued, because when you access it a generic search page is displayed instead and that is common to situations when the domain expired as well.
You might have to look for other applications from the same category, and luckily there are plenty available: http://macdownload.informer.com/search/image+viewer
