ORA-27373: unknown or illegal event source queue
Cause : The source queue specified for the event based job or event based schedule was either not found or was of the wrong type.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Check if the queue exists. If it does make sure it is a multiple consumer queue and it is a post 8.1 compatible queue. Single consumer queues and old-style queues cannot be used as event source queues.
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.