I thought my need was pretty simple, but I couldn't find a solution...
How can I make ASP-classic errors appear in Windows Event Log ? I need it on Windows-server-2000 and Windows-Server-2003.
In Windows Server 2003 (IIS 6) there is the Metabase property AspErrorsToNTLog (boolean).
See this Microsoft TechNet article: AspErrorsToNTLog Metabase Property (IIS 6.0).
This article here explains how you can change the IIS metabase file in IIS 6: Modify the IIS Metabase Directly (IIS 6.0)