ORA-24032: object string exists, index could not be created for queue table string
Cause : Oracle AQ tried to create an index with the name specified in the error message. The index could not be created for the specified queue table because a object exists with the same name.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Drop the object specified in the error message and retry the command. You can also choose a different name for the queue table.
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.