All Oracle Error CodesOracle DBA Forum

ORA-31634:

job already exists
Cause: Job creation or restart failed because a job having the selected name is currently executing. This also generally indicates that a Master Table with that job name exists in the user schema. Refer to any following error messages for clarification.
Action: Select a different job name, or stop the currently executing job and re-try the operation (may require a DROP on the Master Table).