Cron does not execute, how to handle

Cron does not execute, urgent urgent
FREEBSD System:
Wrote a backup database of the file ' Mysqlbak '
File contents:
tbt= ' Date +%y_%m_%d_%h%m%s '
MYSQLDUMP-UTTT-PTTT TTT--default-character-set=gb2312>/8799/uujia_$tbt.sql

Direct input Mysqlbak can perform this backup,
But in the cron can not be executed, do not know what is the reason, please help me to analyze.
This is how I set up the plan crontab.
Crontab-e
*/1 * * * * Runmysqlbak

Waiting

------Solution--------------------
All plus absolute paths.
------Solution--------------------
*/1 * * * */usr/local/etc/mysqlbak.sh

In addition, the mysqldump in your backup script uses an absolute path:
/usr/local/bin/mysqldump-uttt-pttt ......... ...............

