PHP 4.3.4 is distributed with SuSE 9.1. Session support is supposed to be
default in PHP 4+ ... but

In a script I'm writing, my page starts with the lines

<?php
session_start();
$_SESSION['curKey'] = 0;
?>
......

When the page is loaded, I get the error message

"Fatal error: Call to undefined function: session_start()
in /srv/www/htdocs/lookups/index.php on line 2"

which corresponds to the call to session_start(). session.auto_start = 0 in
my php.ini, but an explicit call to session_start() should start the
session according to the documentation, so I don't see anything wrong.
Anybody have an idea of what I'm missing?

tia
---Michael