Index: install.php
===================================================================
RCS file: /cvs/drupal/drupal/install.php,v
retrieving revision 1.237
diff -u -p -r1.237 install.php
--- install.php	17 Feb 2010 04:19:51 -0000	1.237
+++ install.php	22 Oct 2010 01:40:38 -0000
@@ -16,6 +16,12 @@ define('DRUPAL_ROOT', getcwd());
  */
 define('MAINTENANCE_MODE', 'install');
 
+// Exit early if running an incompatible PHP version to avoid fatal errors.
+if (version_compare(PHP_VERSION, '5.2.4') < 0) {
+  print 'Your PHP installation is too old. Drupal requires at least PHP 5.2.4. See the <a href="http://drupal.org/requirements">system requirements</a> page for more information.';
+  exit;
+}
+
 // Start the installer.
 require_once DRUPAL_ROOT . '/includes/install.core.inc';
 install_drupal();