IIS Events and Error Messages
IIS events and error messages are documented verbatum in the IIS administration guide that is included with IIS. Or, see the topic Events Reference on the Microsoft TechNet Web site.
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 Event Messages
IIS event messages are recorded in the Application log of the Windows Event Viewer. The Application log can be parsed programmatically to search for specific IIS event messages that are of concern to an IIS administrator.
IIS Error Messages
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.