ORA-27485: argument string already exists at a different position
Cause : An attempt was made to create or replace an argument with a name that is already used by an argument at a different position.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Use a different name for the argument or drop or alter the argument which already exists with this name and then reissue the 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.