After you upgrade your Microsoft Exchange 2000 Server computer to Microsoft Exchange Server 2003, the virtual directories that are used by Microsoft Outlook Web Access, by Microsoft Outlook Mobile Access, or by Exchange ActiveSync may not be created in Microsoft Internet Information Services (IIS).
Additionally, when you try to start the System Attendant service (Mad.exe) in Exchange Server, the following event may be recorded to the application log:
Event Type: Error
Event Source: MSExchangeSA
Event Category: General
Event ID: 2059
Description:
The DsProxy dll is required but cannot be loaded, error 'c0070000'.