The HTTP server encountered an unhandled exception while processing the ISAPI Application 'E:\php4\php4isapi.dll'. 

I called the following script:
session_start();
session_register("SESSION");

if (! isset($SESSION)) {
	$SESSION["count"] = 0;
	echo "<li>Counter initialized, please reload this page to see it increment";
} else {
	echo "<li>Waking up session $PHPSESSID";
	$SESSION["count"]++;
}
echo "<li>The counter is now $SESSION[count] ";

phpinfo() works fine. Any call to session functions fail.