Hi Peter,
In this case it would be any/every drawing object in a text box, callout, comment, footnote, or endnote. They shouldn't be too hard to find.
Well, you could try installing Open Office and using its tools to save in the doc format, but don't hold your breath - it's likely to choke on the same issues and, even in documents that don't have them, is more likely to give a less faithful conversion than is the MS product.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]