ORA-19594: control file already included as string
Cause : The control file is already specified for inclusion in this backup or restore conversation. A backup or restore conversation may process only a single instance of the control file.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
No action required - the conversation is still active, and more files can be specified.
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.