ORA-23537: function or procedure string is not allowed to be invoked from this site.
Cause : This function or procedure is restricted to the backend or middle tier site
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Connect to the proper site before calling this function or procedure.
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.