A family of Microsoft word processing software products for creating web, email, and print documents.
2010 and all other MS revisions STINK.
In my case none of the above registry tweeks worked nor did any other solution for that "one specific document" error with that issue; all other Word document openings worked fine.
My solution, after trying everyone else's was a simple importing or opening the file with that problem, doing a minor edit of a word or space.
Then resaving the document and Word recognized the file without the error.
What caused it to begin with has to be a coding error within MS Word that no-one has bother to consider vs coming up with idiotic solutions.
How's that for thinking outside the box.