ORA-24806: LOB form mismatch
Cause : When reading from or writing into LOBs, the character set form of the user buffer should be same as that of the LOB.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Make sure that the buffer you are using to read or write has the same form as that of the LOB.
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.