ORA-16507: unrecognized request identifier
Cause : The specified request identifier was not recognized by the Data Guard broker.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Reissue the request using a valid request identifier.
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.