Do you have any patches for Windows Server 2000 running Exchange 2000? Do you have the procedure manually run the update on the Exchange 2000?
There is a patch available for Win2000. However it is only available to customers who what purchased the Extended Hotfix Support - DST contract. $4000 is the cost of the Extended Hotfix Support-DST contract. That gets you access to ALL DST-related hotfixes for products in the extended support phase of the lifecycle. That includes Windows 2000, Exchange 2000, Outlook 2000, and Outlook 2002. You can purchase EHS-DST by calling 800-MICROSOFT. Otherwise you can follow the manual workaround described in http://support.microsoft.com/kb/914387.
For Windows 2000, you can also follow KB914387 to manually patch your Windows 2000 OS. For Exchange 2000 CDO patch there is no alternative. The Exchange CDO update is a binary. There is no work around for it.