"Create User" gives ORA-01031: insufficient privileges for user sys

Question

I am on Oracle 11g db, 11.1.0.6 and login successfully using sys/password as sysdba. This login is successful.
[oracle@RH5-32-OR bin]$ ./sqlplus sys/abcd1234 as sysdba
SQL*Plus: Release 11.1.0.6.0 - Production on Thu Jan 21 06:06:51 2010
Connected to:
Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options
However, I cannot create a new user, getting error about insufficient privileges. I though since this is a sys login with role DBA, it should be allowed to create user.
I also logged in to enterprise manager console using the same credentials, and navigated to: Security->Sys.
- Under the system tab, and can see "Create User" granted.
- Under the role tab, there is DBA granted.
SQL> create user myuser identified globally;
create user myuser identified globally
ERROR at line 1:
ORA-01031: insufficient privileges
Where to check for previleges? And how to debug. I am really very surprised.
Thanks.

Answer 1

I don't have first hand experience of using Database Vault myself, but according the manual the default setup prevents SYSDBA from creating users when Database Vault is enabled (which I would guess is the case based on the banner posted above) This behaviour can be modified by the Vault administrator.
http://download.oracle.com/docs/cd/B28359_01/server.111/b31222/db_objects.htm#BEIJIFGA