Cron tasks run with a very limited user environment. No user profile will be sourced by cron to run before running your task. Unless the task is very lightweight, please consider running your cron tasks through batch as described below

In particular, the $SCRATCH environment variable IS NOT SET.  If you need to use $SCRATCH in your cron job then please specify the actual path to your $SCRATCH (i.e., /scratch/...) and DO NOT USE the environment variable !