I just recently tried looking up 'Heroes' by David Bowie and all of the tabs have been blocked in my country.
I can't understand why an artist/label doesn't want their work to be available to people outside of the country that it is produced in (Xenophobia in music?!?), however, if that's the way things go then fine.
The problem is David Bowie is from the UK, how the hell could he be unavailable in my country if he's from the country that I frigging live in.

Is UG seriously turning into Youtube now? Blocking music to people on the grounds that it isn't available in their country, when the music itself is from that exact country.

Are you trying to tell me that, somehow, these artists are going to the north pole to record these albums, so that it's only available to Inuits.
UG can only distribute tabs in countries that they have secured the license to distribute them in. If they distribute tabs that they don't have the license for they can get in legal trouble. If you want the site to stick around then you'll suck it up and deal with it.
login through a proxy like 'hidemyass.com' and the server wont be able to trace what country your from and you can get any tab.