I have the same problem on a 2nd gen ipad. Notificatins were updating, but the update screen was blank white.
As a short-term solution, you can update your apps manually.
From the applications app, choose the adjacent "purchased" tab. Scroll through your purchased apps (mine shows some recent ones by default, but to see the rest, I clicked on the alphabet index on the left).
Apps with updates will show "update" or "installing" instead of "open" (or the cloud symbol for apps not currently installed on the device). Click on "update" to start. If it says, "installing" the update was started but didn't finish. Tapping on the apps icon from the home page (or whichever page) will restart the update for those.
That said, what a pain in the butt (though much easier than other solutions I have seen posted-- deleteand reinstall ALL your apps?! Really?). This should be corrected, obviously.