I want to add this to the hcaccess file, but it's not there, where the tutorial says

[g1smd]

Try this. A few additions and a minor tweak:

ErrorDocument 404 /index.php?main_page=page_not_found

RewriteEngine on

# Fails with 404 error, any URL request that includes
# record_company.php/password_forgotten.php
# at any folder depth or root.
RewriteRule ^([^/]+/)*record_company\.php/password_forgotten\.php$ /page-does-not-exist [L]

# Fails with 404 error, any URL request that includes
# images/wp- with 'wp-' being anything that ends with '.php'
# this allows for images named such as 'wp-header.jpg' to work
RewriteRule ^([^/]+/)*images/wp-([^.]+)\.php$ /page-does-not-exist [L]

There may be other rules elsewhere on your site that interfere with it.

[JDog21]

Thanks for the advice on upgrades. I will follow it. I have download 1.3.9. Before I unzip it and FTP it, I am backing up my existing database, and image files.

What should I expect when I do this installation? I'm pretty sure my admin file will be named admin again, but I can fix that......