ORA-01031: insufficient privileges while doing / sysdba

I copied one oracle home to some other server/mount and did the clone of binaries.
After completion when I was trying to log in to SQL as sysdba to create database here. There I found following message.


$sqlplus '/ as sysdba'

SQL*Plus: Release 11.2.0.3.0 Production on Fri Feb 7 05:12:22 2014

Copyright (c) 1982, 2011, Oracle.  All rights reserved.

ERROR:
ORA-01031: insufficient privileges

Enter user-name:



Looking like some permission issue. Checked the user and OS permission of files, which were looking OK.
SQLNET.ORA too looked ok, then found following.

Reason:- Running clone on binaries has overwritten $ORACLE_HOME/rdbms/lib/config.c, and it was missing group values.


#define SS_DBA_GRP ""
#define SS_OPER_GRP ""

Solution:- Changed it to

#define SS_DBA_GRP "oinstall"
#define SS_OPER_GRP "oinstall"


Then run $ORACLE_HOME/bin/relink.


On completion, 


$sqlplus '/ as sysdba'

SQL*Plus: Release 11.2.0.3.0 Production on Fri Feb 7 07:02:55 2014

Copyright (c) 1982, 2011, Oracle.  All rights reserved.

Connected to an idle instance.

SQL>

Worked well.