Word 2003, feature not installed error

[Bob Graham]

I have Word 2003 installed, with Word 2000 still on the same machine.

When I use the "Look up" feature, it tells me the thesaurus is not
installed, even though it is. It asks me if I want to install the feature.
If I say yes, it asks for the Office 2000 disk (not 2003).

If I say no, it goes ahead fine.

This must be an issue with having both versions on the machine. How can I
get rid of this nag? It also happens with some other features.

Bob