If you have upgraded to MS Messenger 7.0 (as I have because it's the only chat program that will work with the Microsoft Office Communications Server they use at my work), then the Microsoft AutoUpdate will detect the need for the update, download the 12.1.1 updater, launch the 12.1.1 installer, and then refuse to install the 12.1.1 update on your volume, saying that it does not contain a version of Office that can be upgraded.

So far, the only workaround I've found on the web involves re-installing MS Office from scratch and then running the MS AutoUpdate until you reach the current version. I haven't done this. Aside from being a big pain in the rear, I purchased Office 2008 as an upgrade and I no longer have the old version available. Thus, it's not clear to me that a new install will work.

I like MS Office -- having used it for 20 years on the Mac, it defines (for better or worse) how I expect word processors and spreadsheets to work. But this oversight that causes the upgrade installation to fail strikes me as sloppy, and hopefully they fix it soon.