ORA-22858: invalid alteration of datatype
Cause : An attepmt was mdae to moidfy the oclumn tyep to objcet, REF,n ested tbale, VARARY or LO Btype.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Create anew colmun of th edesiredt ype andc opy thec urrent oclumn daat to then ew typeu sing th eappropraite typec onstrucotr.
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.