Summary
This is usually caused when two versions of Office were installed, and one was uninstalled after the other was installed. This creates a mismatch in the library's the applications use to function correctly.
Body
This is usually caused when two versions of Office were installed, and one was uninstalled after the other was installed. This creates a mismatch in the library's the applications use to function correctly. (Normally you should only install a newer version AFTER the old one was installed to insure the correct pointers exist in the registry.)
Step One: Launch Control Panel
Step Two: Select Programs and Features
Step Three: Select the Microsoft Office currently installed
Step Four: Run Repair