Jag hade samma problem, hittade detta på MacUpdate:
1. Download the update from Microsoft and DRAG the OFFICE 2008 12.1.4 Update FILE FROM THE DMG FOLDER ONTO YOUR desktop - you will be modifying the file, so need to be able to edit and save it
2. Right click on the Updater ON YOUR DESKTOP and click "Show Package Contents".
3. Navigate to Contents -> Resources. You need to modify the script: package_updatable.
4. Remove these TWO lines using Text Edit, BBEdit or similar:
if not found_valid_version:
sys.exit(48)
Save these changes to the Updater [ALLOW IT TO OVERWRITE WHEN ASKED] then close. Now it will update.
Fungerade alldeles utmärkt för mig!
/Robban