Backup archive logs from active standby

I am trying to back up archive log files from an active standby database, version 11.2.0.3 on RH Linux 5.8 64 bit,  The standby is two node RAC. Below is the script. The rman was connected to both scan listener and catalog. Any ideas?

RMAN> run {

2> allocate channel c0 device type disk format '/tmp/arch%U.bak';

3> backup as compressed backupset archivelog all;

4> }

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-03113: end-of-file on communication channel

Process ID: 10858