Note: Creating custom error pages when FrontPage Extensions are on is not recommended. FrontPage uses the .htaccess file for the Publish Web feature. If you overwrite the .htaccess file you will no longer be able to Publish your web.
Creating the error pages
Using your standard html editor navigate to you local web site root.
Create the directory called "errors" and enter this directory.
Using your standard html editor create the following files and save them to your newly create "errors" directory: