Help with Moodle on Mac OS X server - PhP issue

First off, ensure that local DNS services are working. If DNS is not working, then various services offered by OS X Server can be flaky. Launch Terminal.app and issue the following diagnostic command:

sudo changeip -checkhostname

It's common for folks to skip DNS setup or to reference ISP DNS services, which usually gets them in trouble, and have a much larger project fixing DNS-level errors.

OS X 10.8.4 should have php 5.3.15 and PostgreSQL 9.2.1, the versions of both appear to exceed the Moodle minimum requirements of 5.3.3 and 8.3, respectively. To verify the php version, use the usual "<?php phpinfo() ?>" script. For PostgreSQL, the brute-force command-line version check is "psql --version" command.

Put another way, I'm not sure why you're considering upgrading components — which can be problematic — if you're already running OS X Server 10.8.4 as implied by the footers of your posting.

Have a backup before starting the installation, as mistakes happen and having a backup of the whole disk means a faster recovery and an easier ability to start anew.