[Sergi]

I have been having the same error today trying to save a document. I have
tried with different computers, so I am pretty sure that the problem is not
only in my computer. Also, I have been reading that more people are having
the same problem problem but no solution has been found.

When does the problem occur?
Trying to save a document with Word 2007.

With all the documents?
No. I can save some documents, but some others not. You might be able to
recreate the same problem doing those steps:

1. Create New Document.
2. Start a numbering list. Write something
3. SHIFT+Enter
4. Insert equation. Write something into the equation.

Then try to save. I haven't been able. Does somebody has a solution for that?