Word 2008 A file error has occurred. Check your network connections . . .

Word 2008 12.1.2 throws an error dialog when trying to save a docx file:

"A file error has occurred. Check your network connections or make sure the disc is properly inserted and not defective (name offile.docx)"

Newsgroups recommend to trash the Normal.dotm and let Word re-create that template but that doesn't solve the problem.

Newgroups also recommend specifying the file location of User Templates. That's doesn't help either.

A new file, however, does not appear to be a problem after following these suggestions. So there may be something wrong with my file.

I suspect it has something to do with the gutter and mirror margins because when these features are manipulated, Word 2008 inserts an extra "section next page" that I am not happy with, and the page numbering and sometimes section numbering gets thrown off.

Actually, I don't care WHY it's happening. I just want to know HOW to avoid this error. I cannot save changes to an important docx file anymore.

My work around: "Save as" to doc format and continue working!

However, I would prefer to keep working in docx format because Word bloats doc files incessantly, but docx seems to keep file size in check.