So if you are using ADSI to invoke EnumAppsInPool to get all the applications assigned to a given application pool. It might result in a “Unknown name. (Exception from HRESULT: 0x80020006 (DISP_E_UNKNOWNNAME))” error.

So what I have found is that if you are calling the invoke from a Windows XP machine it will cause this error.  But if you making the call from a Windows Server 2003 (or Longhorn Server) machine it will work.  I am looking into if this is a bug or by design. 

The IIS6 management on XP ( download does NOT fix this issue.