I did notice that mapisvc.inf had changed this morning and I suspect that was the cause of the wrong mapi32.dll being used. However, we don't know why that file was updated.
The fix was relatively easy I copied mapi32.dll from C:\Program Files\Exchsrvr\bin to C:\Windows\System32. This is done normally as part of the Exchange 2003 installation process.
Full text of the error was:
Exchange detected that "c:\windows\system32=MAPI32.DLL" is not theIn most cases, this error is the result of installing Outlook on an Exchange 2003 server and the Outlook mapi32.dll overwrites that from Exchange. That was not the case here.
correct version required to run Exchange System Manger or Exchange Server
2003. This may cause failures in Exchange System Manager, affect
availability of your server, or both. For more information see Microsoft
Knowledge Base article Q266418 at http://support/microsoft.com
For more information: