Cron Job

[BulliM]

I try to run an own cron job from /core/includes/cron, but I couldn't get it run.

PHP Code:

<?php if (!defined('VB_ENTRY')) die('Access denied.');

$timenow = vB::getRequest()->getTimeNow();

$conditions = array();

$assertor = vB::getDbAssertor();

$rows = $assertor->select('userfield', $conditions, false, array('field1', 'field2', 'field3', 'field4', 'field6', 'field7'));

I get no result and script aborts at last line. userfield contains all columns in array. No clue what the problem is.