BEGIN 
  DECLARE
    l_instance_no number;
  BEGIN
    SELECT instance_number INTO l_instance_no FROM v$instance;    
    INSERT INTO OWBSYS.OWBRTPS(key, value) VALUES ('%vers[' || l_instance_no || ']','%home');
    COMMIT;               
  EXCEPTION
  WHEN DUP_VAL_ON_INDEX THEN
    DBMS_OUTPUT.PUT_LINE('OWBRTPS entry already exists for %vers['||l_instance_no||']');
  END;
END;
/