SQL & PL/SQL

When I execute the below procedure I am getting the below mentioned error

SQL> CREATE PROCEDURE sql_tuning_demo (
  2  hint_in IN VARCHAR2 DEFAULT NULL
  3   ) AS
  4  
  5  v_task VARCHAR2(30);
  6  v_sql  CLOB;
  7  
  8  BEGIN
  9  
 10   /* Assign our de-dupe statement... */
 11  v_sql := ' DELETE /*+ ' || hint_in || ' */ FROM t1 a
 12 WHERE a.ROWID > ( SELECT min( b.ROWID )
 13 FROM t1 b
 14 WHERE a.owner = b.owner
 15 AND a.name = b.name
 16 AND a.type = b.type
 17 AND a.line = b.line )';
 18  
 19   /* Drop the task in case we are re-running... */
 20   BEGIN
 21   DBMS_SQLTUNE.DROP_TUNING_TASK(
 22  task_name => 'sql_tuning_task'
 23   );
 24   EXCEPTION
 25   WHEN OTHERS THEN -- ORA-13605
 26   NULL;
 27   END;
 28  
 29   /* Create a SQL Tuning task for our SQL... */
 30  v_task := DBMS_SQLTUNE.CREATE_TUNING_TASK(
 31  sql_text  => v_sql,
 32  time_limit  => 1,
 33   scope   => 'COMPREHENSIVE',
 34  task_name  => 'sql_tuning_task',
 35  description => 'Demo of DBMS_SQLTUNE'
 36   );
 37  
 38   /* Execute the task... */
 39   DBMS_SQLTUNE.EXECUTE_TUNING_TASK(
 40  task_name => 'sql_tuning_task'
 41   );
 42  
 43   /* We want to run this again... */
 44   ROLLBACK;
 45  
 46  END sql_tuning_demo;
47  /

Error details :

ERROR at line 1:
ORA-13616: The current user scott has not been granted the ADVISOR privilege.
ORA-06512: at "SYS.DBMS_SYS_ERROR", line 86
ORA-06512: at "SYS.DBMS_ADVISOR", line 941
ORA-06512: at "SYS.DBMS_SQLTUNE", line 622
ORA-06512: at "scott.SQL_TUNING_DEMO", line 95
ORA-06512: at line 1

Please help me on this .

Thanks in advance ............