You mentioned in your posting that the same thing happened to you during the 12.1.1 update. How did you resolve it the last time?
The known causes for seeing this issue is like the other commenter said: a) you moved your Office 2008 folder, b) You have used tools that may be removing components from Office and other programs (to save space), or c) Renamed any files or folders.
Your information will be helpful in our continued efforts to reduce this incidents.
Microsoft Mac BU
(Version 12.1.2)