ORA-22856: cannot add columns to object tables
Cause : An attempt was made to add columns to an object table. Object tables cannot be altered to add columns since its definition is based on an object type.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Create a new type with additional attributes, and use the new type to create an object table. The new object table will have the desired columns.
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.