If you get this message, it appears to be caused by a routine trying to limit calls to a max duration but if the script does not get the default 14400 value but zero it cuts off the call.
To stop this behaviour # out the line in /etc/cron.d/sark file.
Jeff is there a way of blocking it's reactivation during reinstalls or upgrades?
Also maybe changing the syslog output from "Out of Credit" to something like "Max call duration reached" along with a reference back to the srkEnforcer script seeing as this was logged in the system log and not asterisk?