ORA-23536: the object "string"."string" is not cached at the middle tier as expected.
Cause : The object may have been dropped or renamed at the back end after dbms_ias_inst.start_ias_inst was executed.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Check the validity of the object at the back end and retry the instantiation.
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.