Ah ha! I've found that I can get it working with using a relative path to the script in cron.ini: path = \www\app\cron.php ...rather than... path = http://localhost/app/cron.php I had to add an "extension=php_mysqli.dll" line to the php-cli.ini file (and set the timezone), so that's why it wasn't working before using the relative path. Still can't understand why it didn't work using the http path, but at least it's working.