ORA-25456: rule set was modified or evaluation terminated for iterator: string
Cause : An attempt to get rule hits was made, which failed because the underlying rule set was modified after the iterator was returned.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Try again after re-evaluating the rule set.
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.