It’s quite possible that you may get timeouts when your PHP cron job runs. If that happens, place this at the top of your script
<?php
set_time_limit(0); //0 = run forever
?>
This will allow your script to run to completion, ignoring timeouts. Jobs executed here at Cronless are run under this directive, but your own web server may timeout if you fail to put that in as well!
If you find that this isn’t enough and you still get timeouts (some hosts are disabling this PHP function), you can help by limiting your script output as much as possible. (less than 4kb is ideal)