ORA-29394: session id string and serial# string do not exist
Cause : Invalid session id and serial# were specified as arguments to procedure SWITCH_CONSUMER_GROUP_FOR_SESS of package DBMS_SYSTEM.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Specify valid values from the view V$SESSION.
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.