ORA-16778: redo transport error for one or more databases
Cause : The redo transport service was unable to send redo data to one or more standby databases.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Check the Data Guard broker log and Oracle alert log for more details. Query the LogXptStatus property to see the errors.
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.