ORA-20000

I ran job under user "TEST":

    dbms_scheduler.create_job(job_name => v_job_name,
         job_type            => 'EXECUTABLE',
         ...
    );

    dbms_scheduler.set_attribute(v_job_name, 'destination', 'SYS.TEST_DESTINATION');
    dbms_scheduler.set_attribute(v_job_name, 'credential_name', 'SYS.TEST_CREDENTIAL');
    dbms_scheduler.set_attribute (v_job_name, 'logging_level', DBMS_SCHEDULER.LOGGING_RUNS);

    dbms_scheduler.enable(v_job_name);

And I got the errror:

ORA-06512: at "SYS.DBMS_ISCHED", line 4395
ORA-06512: at "SYS.DBMS_SCHEDULER", line 2803
ORA-27476: "SYS.TEST_CREDENTIAL" does not exist

Cause: User "TEST" not have permissions to execute credential.

Action: User "TEST" had the following rights:

GRANT EXECUTE ON SYS.TEST_CREDENTIAL TO TEST;

I got the error:

EXTERNAL_LOG_ID="job_173118_9",
USERNAME="DB_HOST\user_agent",
STANDARD_ERROR="Launching external job failed: Invalid username or password"

Cause: On Windows, the host user that runs the external executable must be assigned the Log on as a batch job logon right.
http://docs.oracle.com/cd/B28359_01/server.111/b28310/scheduse002.htm#ADMIN12397

Action:  In the Control Panel, open Administrative Tools, then Local Security Policy.  Beneath Security Settings, open Local Policies and highlight User Rights Assignment.  Locate Log on as a batch job. Open the properties and add any users that need this right.  When finished, save your changes and close the Local Security Settings window.

I got an error:OpenService failed - The specified service does not exist as an installed service.

C:\app\product\11.2.0\client_2\bin>schagent.exe -registerdatabase dbag 8080
Agent Registration Password ? *******************
*
Oracle Scheduler Agent Registration for 11.2 Agent
Agent Registration Successful!

C:\app\product\11.2.0\client_2\bin>schagent.exe -unregisterdatabase dbag 8080

1] dbag

Enter the number of the database being unregistered or 0 to cancel:
1
Oracle Scheduler Agent Unregistration for 11.1 Agent
Agent Unregistration Failed!
Error: ORA-27452: 192 is an invalid name for a database object.

C:\app\product\11.2.0\client_2\bin>schagent.exe -unregisterdatabase dbag 8080
No registered database v11.2 or higher to be unregistered.

C:\app\product\11.2.0\client_2\bin>schagent.exe -removeagentservice
OpenService failed - The specified service does not exist as an installed service. (0x424)

SQL> select * from all_scheduler_external_dests;

DESTINATION_NAME  HOSTNAME           PORT IP_ADDRESS       ENABLED COMMENTS
----------------- ---------------- ------ ---------------- ------- ---------------------------------------------------------
AGENT_1           192.168.100.102   65001 192.168.100.102  TRUE    Registered on 30-JAN-14 11.06.31.426000 AM EUROPE/MOSCOW

SQL> 

begin
  dbms_scheduler.drop_agent_destination(destination_name => 'AGENT_1');
end;

SQL> 

Remove windows service:

C:\app\product\11.2.0\client_2\bin>sc delete OraClient11g_home2_OracleSchedulerExecutionAgent
[SC] DeleteService SUCCESS