RMAN-06172: no autobackup found

While performing disaster recovery I get the error RMAN-06172 as below.

RMAN> restore spfile to pfile ‘/oracle/app/oracle/product/10.2.0/db_1/dbs/initARJU.ora’ from ‘/backup1/snap/june/ctl_sp_bak_c-448149146-20080607-00’;
Starting restore at 27-AUG-08
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=36 devtype=DISK
RMAN-00571: ====================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ====================================================
RMAN-03002: failure of restore command at 08/27/2008 00:42:41
RMAN-06172: no autobackup found or specified handle is not a valid copy or piece

Cause of The Error
To perform restore operation to a new host you must have at least one autobackup of the controlfile. If you don’t have autobackup of the controlfile then you would not be able to perform disaster recovery. For example if you have snapshot of controlfile backup then you will not be able to restore spfile or controlfile.
Oracle in World: RMAN-06172: no autobackup found.

SSH login without password

a@A:~> ssh-keygen -t rsa

Now use ssh to create a directory ~/.ssh as user b on B. (The directory may already exist, which is fine):

a@A:~> ssh b@B mkdir -p .ssh
b@B's password:

Finally append a’s new public key to b@B:.ssh/authorized_keys and enter b’s password one last time:

a@A:~> cat .ssh/id_rsa.pub | ssh b@B 'cat >> .ssh/authorized_keys'
b@B's password:

From now on you can log into B as b from A as a without password:

a@A:~> ssh b@B hostname

More info at SSH login without password.