I just do not understand why so many people insist on emailing in a Microsoft Word document a text that could have just as well be cut-and-pasted straight in the message subject. Why make everybody's life more complicated?
The problem is the following: Word documents are coded (intentionally?) in such a way that often only a version equivalent or superior to the one that wrote the document needs to be used for reqding the document. The problem has been exacerbated with Word Vista, which saves documents in an entirely new format! If you want to be able to reqd all the documents sent to you, you always need to have the latest version on your computer.
Why would Microsoft make its customers endure this? Word is a product that fundamentally does not need updates, thus would generate minimal sales now that everyone has it. So Microsoft adds some gimmicks, calls it a new version, and then makes its format in some way incompatible with previous ones. The incompatibility seems subtle, as the conversion success rate seems to decline the larger the difference between versions. This just looks like a scheme to fool people into buying more recent versions of Word bloated with useless features.
The policy recommendation: never send Word files. Convert them to PDF (or text) first. Or much more simply, do not use Word at all.