I need to run my script
15 19 * * * pi /usr/bin/python /home/Desktop/miBBDD/time.py
service cron status
I had similar issue some time ago. Delete the user part of your crontab file.
15 19 * * * /usr/bin/python /home/Desktop/miBBDD/time.py
Compare with this answear.
EDIT: just one more thing: is the path valid? Shouldn't it be