Since you have mentioned, I've never had issues before, I am assuming all your permissions are correctly placed.
So, it could be that the temporary (recovery) file that Word creates for every document is damaged or that the preference file for MS Word is also damaged. The former is here:
The latter is here:
Trash all the auto-recovery files and trash the .plist file and launch MS Word again. That should fix it.
And if this doesn't help you, then I would run the MS Word/Office installer and reinstall (or repair if that option is available) MS Word.