Error whilke running SQL advisor

Eror while running advisor

SQL> begin
  2         DBMS_ADVISOR.EXECUTE_TASK('MY_SQLACCESS_TASK');
  3       end;
/

  4  begin
*
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-01843: not a valid month
ORA-06512: at "SYS.DBMS_ADVISOR", line 201
ORA-06512: at line 2

SQL> select SQL_TEXT from table(DBMS_SQLTUNE.SELECT_SQLSET('MY_SQL_TUNING_SET'));

SQL_TEXT
------------------------------------------------------------------------------
with two as ( select count(elpsd_time) hits, trunc(time_ts) time_ts from cert_
t where elpsd_time < 2000 and trunc(time_ts) between trunc(trunc(sysdate,'mm')
-1,'mm') and trunc(sysdate,'mm')-1 group by trunc(time_ts) ), five as ( select
 count(elpsd_time) hits, trunc(time_ts) time_ts from cert_t where elpsd_time <