It seems that when a script die()s, it does not generate any output - running it from the command line produces nothing and running it from the cronjob does not produce email in case cron mail is configured.
All cron scripts have the code that manages KB_HOME, and that code die()s if unable to do its work. I suggest moving the message string from the die() argument to the separate echo statement before that die() to ensure that it will be outputted and the person that configures the killboard will immediately see the problem.