You often have to debug experiments like this by looking in at least three places:

1. The Apache server “access” and “error” logs.
2. Anything that might be output to the OS/X “console” utility.
3. The information gleaned from a client-side debugger such as Firefox’s FireBug plug-in, which allows you to delve into exactly what the server actually sent.

Once you clearly see the problem, a resolution is usually fairly easy.   “Aye, but there’s the rub...”

Now, obviously, “nobody in the real world actually does it” quite the way you’re doing it now, although I do applaud you for trying it this way first.   (Yours is a sort of Linux from Scratch approach, and I know that I learned more from that “sip from the firehose” than any book or class could possibly have taught ... and faster, too.)   There are many frameworks, including the venerable CGI::Application, and as you continue your quest you might find it useful to check-out some of the source code of those packages.   See what kind of high-level abstractions they offer to the application programmer, then see how they implemented them.