ORA-28156: Proxy user 'string' not authorized to set role 'string' for client 'string'
Cause : A proxy user has not been granted the right to use a role on behalf of a client.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Execute the command ALTER USER
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.