I have a script that checks if pptp vpn is running , and if not it reconnect the pptp vpn , when i run the script manually it execute fine , when i do set a cron job , is no
finally i found a solution ... instead of entering the cronjob with
crontab -e
i needed to edit the crontab file directly
nano /etc/crontab
adding e.g. something like
*/5 * * * * root /bin/bash /var/scripts/vpn-check.sh
and its fine now!
Thank you all for your help ... hope my solution will help other people as well.