rman doesn't allow connection through the listener for SYSBACKUP users.
With the SYSDBA user this works fine:
oracle@medo admin]$ rman target sys@local
Recovery Manager: Release 12.1.0.1.0 - Production on Sat Feb 22 18:35:14 2014
Copyright (c) 1982, 2013, Oracle and/or its affiliates. All rights reserved.
target database Password:
connected to target database: ORA12C (DBID=214280212)
RMAN>
With a SYSBACKUP user, the same thing doesn't work:
[oracle@medo admin]$ rman target system@local
Recovery Manager: Release 12.1.0.1.0 - Production on Sat Feb 22 18:36:18 2014
Copyright (c) 1982, 2013, Oracle and/or its affiliates. All rights reserved.
target database Password:
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00554: initialization of internal recovery manager package failed
RMAN-04005: error from target database: