Thanks pgorule- that was exactly the sort of thing I was hoping someone would tell me about.
Ken- it is possible that the translation feature differs in 2000 and 2003 versions to the point that it causes incompatibility. The Some documents need to be translated into Spanish, and the person who owns Office 2003 can't get the feature to work right in Office 2000, but if she does something in 2003, no one else can open it. I'll try pgorule's suggestion and see if they can open translations then.
Jill