IIS Events and Error Messages
For information about how to resolve an event or error message, search for the message text at Microsoft Communities or Microsoft Help and Support. If the error is logged to the event viewer, you can also click the Help and Support link in the Properties page for the event to find information about the error.
IIS error messages are displayed in the client browser and logged to the IIS log files.
Additionally, errors can be recorded in the Application log of the Windows Event Viewer if the metabase property AspLogErrorRequests is set to TRUE. Both the IIS log files and the Application log can be parsed programmatically to search for specific IIS event messages that are of concern to an IIS administrator.