ORA-00204 ORA-00202 ORA-27071 HP-UX Error: 9: Bad file number

Problem Description
RMAN backup fails with ORA-00204 ORA-00202 ORA-27071 HP-UX Error: 9: Bad file number as below.

Recovery Manager: Release 11.1.0.7.0 - Production on Fri Jan 29 00:01:15 2010
Copyright (c) 1982, 2007, Oracle. All rights reserved.
RMAN-06900: WARNING: unable to generate V$RMAN_STATUS or V$RMAN_OUTPUT row
RMAN-06901: WARNING: disabling update of the V$RMAN_STATUS and V$RMAN_OUTPUT rows
ORACLE error from target database:
ORA-00204: error in reading (block 1, # blocks 1) of control file
ORA-00202: control file: '/SID/oradata/APEXP/control01.ctl'
ORA-27071: unable to seek to desired position in file
HP-UX Error: 9: Bad file number

An another version of error message appear while starting RMAN is,
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00554: initialization of internal recovery manager package failed
RMAN-06003: ORACLE error from target database:
ORA-00204: error in reading (block 3, # blocks 1) of control file
ORA-00202: control file: '/SID/oradata/APEXP/control01.ctl'
ORA-27071: unable to seek to desired position in file
HP-UX Error: 9: Bad file number Additional information: 2

Cause of the Problem
The RMAN-06900, RMAN-06901 error occurs when the RMAN couldn't log the output in $rman_output. The actual investigation of the error comes in the associated additional error messages. If you look for additional error message we will see ORA-27071, HP-UX Error: 9: Bad file number. The word 'HP-UX Error: 9: Bad file number' indicates that error is coming from operating system. The OS user who is invoking RMAN don't have OS permission on the control file and hence HP-UX generates bad file number error.

Solution of the Problem
The user who is invoking RMAN don't have write permission on the controlfile. You must need to change permission from operating system. You can do so by issuing,
$chmod 666 /SID/oradata/APEXP/control01.ctl

After you change the permission now try to invoke RMAN command again.
Related Documents:

How to Restore the Controlfile from Backup.

ORA-00214: Controlfile Version Inconsistent on Startup or Shutdown

Controlfile in Oracle Database.

New Feature of 10.2g: Eliminate Control File Re-Creation

Creating controlfile fails with ORA-01503, ORA-01161

Backup Database control file -User Managed

Recover database after only lose of all controlfiles