ORA-25508: database is not mounted
Cause : Database must be mounted to perform ALTER SYSTEM UNQUIESCE command.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Mount the database and retry this command.
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.