ORA-16162: Cannot add new standby databases to protected configuration
Cause : An attempt was made to enable a new standby database destination when the primary database is in standby protected mode.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
The standby database must be added to the configuration before the primary database is opened.
Well, the reason for above error is that i have taken the above script from a 11g database and running it on 10g database. 11g has bring some changes in password management. Below code is executed on 11g and user created successfully, which is expected result.