When the system runs your cron jobs, the current directory is /home/axxxxxxx/ rather than /home/axxxxxxx/public_html. The cron.php program will refuse to work because it can't find necessary .inc files. Adding a chdir command to switch to public_html directory in cron.php will solve this problem. Here's an example:
Code:
<?php
chdir('./public_html/');
include_once './includes/bootstrap.inc';
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);
drupal_cron_run();