Alas, I'm too bold for my own good. I ran into the very same problem and instead of looking down here in the discussion for an answer, I found the httpd.conf.default file contained the missing items. So... I changed it instead of the httpd.conf file as the article suggested. Somehow this resulted in a bad thing. When my machine boots I see the Apache Web Server loading...when I log in and visit the Web Sharing button I find it's "off"...when I try to turn it on it won't go. And the server isn't on. Doesn't serve a thing.
On a brighter note, after having read this discussion I was able to set up Apache, PHP and CGI sucessfully on my TiBook. Now how in heck will I fix my desktop machine? Woe is me.