Hi Jay,
First I have to assume that your webserver is Apache. With this assumption comes another, that your ISP allows you to use .htaccess files in your web space. If those two assumptions are affirmed, then here's a short How-To
Create a web page with your custom text. It's simply that, a normal web page.
Then, create a simple text file and put this type in it. Customize it to your tastes.
ErrorDocument 500 /cgi-bin/crash-recover
ErrorDocument 500 "Sorry, our script crashed. Oh dear
ErrorDocument 500
http://xxx/ErrorDocument 404 /Lame_excuses/not_found.html
ErrorDocument 401 /Subscription/how_to_subscribe.html
Here is an
Explanation of error codes. Note that the above are the most common and if all you want is the 404, then that is the only line you need.
The file with the above error codes must then be named .htaccess. Note the . (dot) before the h. This is necessary. The dot "hides" the file from the casual viewer so unless your FTP program is set to show you hidden files on the server that file will "disappear" as soon as you FTP it over. Note two: send it in ASCII, not binary.
That's all you need to do.
Note three: It's possible that your ISP has already put an .htaccess file in your web space. If this is true, you won't want to overwrite it since you may disable some functionality. If they have done this and they're the least bit concerned that you'll damage that file, the permissions and possibly ownership settings will be such that you can't overwrite it. So, check for this file before you send yours. You can "get" files if you know their name even if you can't see them so try to "get" it first. If you find you can't create one of your own, you'll have to contact the ISP.
Look at these links for examples of custom files:
Example oneExample twoOr, make up a page name after the domain name here at TS and see what happens.
Let me know how it goes.
see ya,