Originally Posted by macropod

Have you tried repairing the Office installation (via Start > Windows Control Panel > Programs > Programs & Features > Microsoft Office (version) > Change > Repair)?

Have you tried running Word in safe mode (i.e. hold down the Ctrl key while starting Word)? If the error goes away, the problem is most likely caused by a rogue third-party addin. Disabling all addins then re-enabling them one at a time until you find the one causing the shutdown problems will reveal the culprit. Replace, uninstall or permanently disable that addin.