ORA-19030: Method invalid for non-schema based XML Documents.
Cause : The method can be invoked on only schema based xmltype objects.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Don't invoke the method for non schema based xmltype objects.
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.