Problem: "Word cannot start the spell checker"

I have had my curret copy of Microsoft for Mac since about the start of the year. I have no problems creating documents, and everything just about works fine.

However, once in a while when someone sends me a Word document and I download and open it, a message pops up that looks like this:

I am then not able to read or edit the document any further because everytime I close this window, it immediately reopens. I am quite confused as (a) it does not happen to documents I create, and (b) it does not even happen to every document someone sends me, only some.

I have tried "using Microsoft Office Installer to install the spell checker", but to no avail - the problem still persists.

Has anyone experienced the same problem and knows how to solve it? Help would be greatly appreciated.

Thanks.