Outlook 2000 is not compatible with Vista. Well documented for over a year:
http://www.outlook-tips.net/howto/vista.htm

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Russ Valentine
[MVP-Outlook]
>I get error message Ox9CD4011D - "An error occurred while attempting to
> open Windows Address Book, unable to find WAB.DLL."
>
> Any ideas on how to fix would be gratefully received - I run Vista Home
> Premium, 32bit.