Sounds like Office 2000 / XP / 2003 is trying to finish off installing some components. This often happens in a multi-user office environment when someone new logs on - Office decides to install some more stuff that it didn't put on before.
Go to Add/Remove Programs in Control Panel, double-click the Microsoft Office entry and then, when the install routine starts, choose the Repair option.
If that results in errors as well, you'll need to run the install routine from the Microsoft Office CD-ROM.
Let us know if that helps