Are you running the GUI updater or the command line? No disrespect to the developers and artists who made the GUI happen, I mean none at all.
I just personally prefer CLI for this kind of thing.
If you're running GNOME, hit ALT - F2 and type "terminal" in the pop up window (do not include quotations). If you're on KDE, you still hit ALT - F2, only you will enter "konsole" instead (again, without quotes).
Once the command line window coughs up, type thusly:
It will then ask you for the root password (usually the password you use to login with, however some machines may have two separate passwords if you set them up this way). Type it in, strike the Enter key, and it *should* update. If not, post back here and let me know.