Codeunit 5054: wrdDoc.MailMerge.OpenDataSource2000 error

Codeunit 5054 will not compile as wrdDoc.MailMerge.OpenDataSource2000 is unknown in the Automation Server (at least the one that comes with Office 2000).

If I change it into wrdDoc.MailMerge.OpenDataSource (delete 2000) it will compile and apparently the mail merge also works.

Does anybody know whether this has any negative implications and why does the standard object not compile??

Thanks in advance.