I use it every day and it is working fine here. For the subscribed groups I have "Get new headers when entering group" enabled in Preferences -> Behaviour. Maybe for the group you are trying there are no new headers.
As previous, try Groups -> Refresh Group List. That should tell if you are connecting to the server.
Even if you have not subscribed to a newsgroup, clicking on one in the "Other Groups" list should come up with a dialog. You can get the same dialog with a right click -> Get Headers.
Hmm...not much activity there...
Edit: Another thought, sort the posts by date (descending) otherwise replies and new posts might get lost in the throng, if sorted by article. The number of posts after the group name should change though when new posts are received.