PHP 4.3.9 $_SESSION values not being retained
Problem: After calling
session_start() and assigning key-value pairs to the
$_SESSION array, calling
print_r($_SESSION) subsequently don’t work.
Solution: Assuming your php.ini session
save_path variables are set correctly, also check for free disk space.
I spent 90 minutes trying to resolve the problem thinking it was a PHP-related issue, but in the end, nullifying the 5+ gigabytes of Apache error logs promptly resolved the problem. Doh!