Same goes for me. Achievements are not showing since a couple Month. I actually didnt care much, but since there is a Thread about it and Scragg posted really quick i thought i would also say something.
Im not going for rating or something, its just that i would like to check out Achievements.. but since there isnt even a friggn "Achievement"-Button its kind of annoying. XD
A lot of people including me have this issue, so looks like given it was 2011, it's ongoing XD It shows the points we got recently but doesn't add them on. I'm about 3k down atm :(