RMAN CLONE / DUPLICATE command failed with RMAN-06403 RMAN-04006 RMAN-04015 ORA-19710 (Doc ID 302922.1)

Cause

When the target database is not mounted, RMAN sets the target database character set to the value specified in the users environment.

Solution

- Ensure that the character set of TARGET database and catalog database are same
- Set the environment variable ORA_NLS10 (ORA_NLS33 for 8i and 9i) at OS level
  If you are using a Oracle8, 8i or 9i version then set the ORA_NLS33 for Oracle10g and higher, set
  environment variable to:
  ORA_NLS10 = $ORACLE_HOME/ocommon/nls/admin/data
- Restart the Listener and Instance after setting the ORA-NLS10.

Note:  The error ORA-19710, can also occur due to incompatibilities in listener versions while connected to target and catalog database.
Explanation : There are distinct differences between an 8i, 9i and 10g listener process and the functionality that each process will recognise ; this will also be true of  the shadow processes that are spawned by each listener as they will inherit the same runtime environment and attributes of the listener.  Where you are having issues with connections to target database running at a different release to that of the listener, the recommendation is to use a
separate listener process and to connect to each target using its respective listener.

Thanks
Srini