ORA-38731: Expected version string does not match string in log header.
Cause : The version of the flashback database log file header was corrupt.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
If you are doing a FLASHBACK DATABASE, then the flashback cannot be performed because of the corrupted log. A restore and an incomplete recovery must be performed instead.
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.