ORA-19694: some changed blocks were not found in the change tracking file
Cause : A backup or copy found that some changed blocks had not been recorded in the change tracking file. The details of which files and blocks are affected will be in an Oracle trace file.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
This indicates that there is a problem with the change tracking feature. Disable change tracking and re-start the backup.
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.