@flashrob, You’re right, thanks! They do work now; seems to have resolved itself. It also seems that one of the plugins was responsible. I don’t know which one, but for @asvwebdesign that might be worth checking into as well.
The same issue happens for me. It appears that since the last few update the Tabs have been “broken”. I’ve only recently noticed it though. I use it extensively on my website to separate different elements.
Some of the pages affected:
http://wp.me/P2Vm8L-g6
http://wp.me/P2Vm8L-mm
I’ve been looking for an alternative, but nothing’s on a par with this plugin. It’s unfortunate.