This happened with the previous update, 12.1.1. Apparently a widespread problem, I reinstalled Office and was able to install that update. I haven't messed with any Office-related files that I'm not supposed to. Now I've got the same thing again. The error message is, "You cannot install Office 2008 12.1.2 Update on this volume. A version of the software required to install this update was not found on this volume." Do I need to reinstall this thing every time?