You are trying to access the install via a file url:
file://home/cnorton/scratch/install.php.html
That is not going to work. That bypasses the web server and you need the webserver to process the request and pass things to PHP, which then passes the generated page back to the server for delivery to the client (your browser).
You need to access the file through the server. Something like…
http://localhost/scratch/install.php
… I’d guess, but that can vary depending on how you have Apache configured.
And I’d also recommend giving the server a static local IP (for example, 192.168.1.111) and using that instead of localhost. localhost only works when accessing the site from the same machine that the server runs on and not when accessing from, say, a laptop or other device on the same local network.
I don’t know if this URL is what you’ve typed in or if you are being redirected. If the latter, you have the WordPress configuration wrong somewhere– though I doubt that since you haven’t installed yet.