Problema resolvido:
Altere as permissões em / usr / bin / crontab
[root@dub-ImrORA2 log]# ls -al /usr/bin/crontab
-rwxr-xr-x 1 root root 315640 Dec 20 2011 /usr/bin/crontab
[root@dub-ImrORA2 log]# chmod 4775 /usr/bin/crontab
[root@dub-ImrORA2 log]# ls -al /usr/bin/crontab
-rwsrwxr-x 1 root root 315640 Dec 20 2011 /usr/bin/crontab
Altere o proprietário em / var / spool / cron / oracle
[root@dub-ImrORA2 spool]# cd /var/spool/cron
[root@dub-ImrORA2 cron]# ls -al
total 24
drwx------ 2 root root 4096 Feb 24 11:43 .
drwxr-xr-x 13 root root 4096 Feb 13 2014 ..
-rw------- 1 root root 125 Feb 24 11:43 oracle
[root@dub-ImrORA2 cron]# chown oracle:root oracle
[root@dub-ImrORA2 cron]# ls -al
total 24
drwx------ 2 root root 4096 Feb 24 11:43 .
drwxr-xr-x 13 root root 4096 Feb 13 2014 ..
-rw------- 1 oracle root 125 Feb 24 11:43 oracle
Prova
[root@dub-ImrORA2 cron]# su - oracle
[oracle@dub-ImrORA2 ~]$ crontab -l
55 23 * * 0-4 /home/oracle/scripts/tblspc_usage_rpt.sh >> /home/oracle/scripts/tblspc_usage.log 2>&1