create new DB manually

Hello Oracleies,

I have a small issue with creating a new DB manually; following are my steps, please help me out to find out my problem:

 

1 created folder structure (admin, datafile, redologs, arch,..)

2 created pfile (in dbs folder)

3 created password file (in dbs folder)

4 run sqplus "/as sysdba"

5 startup nomount using pfile

6 create spfile from pfile (in dbs folder)

7 shutdown immediate

8 run sqplus "/as sysdba"

9 startup nomount 

10 exit from sqlplus

11 run sqlplus "sys/password@db_name as sysdba"

SQL*Plus: Release 10.2.0.3.0 - Production on Thu Nov 25 10:29:46 2010

Copyright (c) 1982, 2006, Oracle.  All Rights Reserved.

ERROR:
ORA-01031: insufficient privileges

 

oracle user is part of the oinstall and dba group