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: 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
https://support.oracle.com/
http://www.oracle.com/