Okay, before you do anything I would get a copy of the log for your last update. Are you using apt or one of the GUI updates that uses it? Then:
You should see a list of all the packages updated the last go around (hopefully).
After that you need to make sure we know what package is causing the problem. Hopefully it is something simple like the wacom driver [xserver-xorg-input-wacom]. If it isn't you'll need to figure out what package it is before you try anything else.
If that is it you can look and see if the older packages are available (they should be).
At the bottom of that you should see something like "Provides:" and then a bunch of version numbers. Just go with the 2nd newest version number; copy that down. Then install that version and lock/pin it. Depending on what package manager you use the process will be different, so I suggest googling the specifics from there or posting them in this thread.
apt-cache showpkg xserver-xorg-input-waom
EDIT: If you are wondering how to install a specific version of an application with apt-get it's:
So it would look something like this if you need to do it for the above wacom package:
apt-get install pkg=version
apt-get install xserver-xorg-input-waom=1:0.14.0-0ubuntu2