If you type any type of web address that does exist on your site, a 404
error will occur.
Make sure that you have the correct file name extension. Even the period "."
before the file name extension can sometimes be mispelled to a comma or
something else and it will not work. The incorrect spelling of the file name
extension will also cause this.
Some of the common file name extensions - .htm, .html, .asp, .php
When you perform a "save as", you can see all the different file name
extensions. For common sites, it is a good idea to stick with .htm or .html.
This will allow forms to work and general navigation is easy. .asp files are
for server side scripts for use with databases and such, but the built in
forms in frontpage will not work with a asp extension.
Hope this helps...