backup with scheduler job

Hello,

When i try to backup with scheduler, i am receiving below error.

When i comment out rman commands from my shell script , job succesfully run.

What should  i do to succesfully run this job ?

SQL> exec DBMS_SCHEDULER.run_job(job_name=> 'BackupBeforeEod' );
BEGIN DBMS_SCHEDULER.run_job(job_name=> 'BackupBeforeEod' ); END;

*
ERROR at line 1:
ORA-27369: job of type EXECUTABLE failed with exit code: Operation not
permitted
ORA-06512: at "SYS.DBMS_ISCHED", line 196
ORA-06512: at "SYS.DBMS_SCHEDULER", line 486
ORA-06512: at line 1

#!/bin/sh
ORACLE_SID=MRXXXX
ORACLE_BASE=/u01/app/srvexa
ORACLE_HOME=/u01/app/oracle/product/11.2.0.4/dbhome_1