PLS-00905: object SCOTT.DO_COMMISIONS is invalid

Question

I tried to create a procedure,i didn't get any errors when created.But,when i am executing it i am getting the error
object SCOTT.DO_COMMISIONS is invalid
-- This procedure computes the commissions for salespersons.
-- It prints out the salesperson's code,his or her total sales,
-- and corresponding commission.
-- No inputs. No errors are reported and no exceptions are raised.
/* Logic: A cursor to create a join between PLSQL101_PRODUCT and
PLSQL101_PURCHASE on PRODUCT_NAME column is done.
The result is ordered by salesperson.
Outer loop starts with a new salesperson and inner loop
processes all rows for one salesperson.
CREATE OR REPLACE PROCEDURE do_commissions IS
   commission_rate NUMBER := 2  ;
   total_sale     NUMBER := 0  ;
   current_person CHAR(3):= ' ';
   next_person    CHAR(3)      ;
   quantity_sold  NUMBER := 0  ;
   item_price     NUMBER := 0  ;
   CURSOR sales_cur IS
      SELECT tab1.salesperson,
             tab1.quantity,
             tab2.product_price
      FROM   plsql101_purchase tab1,
             plsql101_product  tab2
      WHERE  tab1.product_name = tab2.product_name
      ORDER BY salesperson;
  BEGIN
       OPEN sales_cur;
       LOOP
         FETCH sales_cur INTO
               next_person, quantity_sold, item_price;
         WHILE (next_person = current_person
                AND
                sales_cur%FOUND)
         LOOP
              total_sale :=
                   total_sale + (quantity_sold * item_price);
              FETCH sales_cur INTO
                   next_person, quantity_sold, item_price;
         END LOOP;
         IF (sales_cur%FOUND)
         THEN
              IF(current_person != next_person)
              THEN
                  IF(current_person != ' ')
                  THEN
                     dbms_output.put_line
                        (current_person ||
                         ' ' ||
                         total_sale ||
                         ' ' ||
                         total_sale * commission_rate / 100);
                  END IF;
                  total_sale := quantity_sold * item_price;
                  current_person := next_person;
               END IF;
            ELSE IF (current_person != ' ')
            THEN
                 dbms_output.put_line(current_person ||
                                   ' ' ||
                                   total_sale ||
                                   ' ' ||
                                   total_sale * commission_rate / 100);
                   END IF;
                END IF;
                EXIT WHEN sales_cur%NOTFOUND;
                END LOOP;
                CLOSE sales_cur;
             END do_commissions;
SQL> @do_commisions
Procedure created.
SQL> EXEC do_commisions;
BEGIN do_commisions; END;
ERROR at line 1:
ORA-06550: line 1, column 7:
PLS-00905: object SCOTT.DO_COMMISIONS is invalid
ORA-06550: line 1, column 7:
PL/SQL: Statement ignoredCan someone explain me why i am getting that error,i did nothing wrong in the coding part

Answer 1

Error message
SQL> select * from dba_errors where name='DO_COMMISIONS';
OWNER                          NAME                           TYPE           SEQUENCE       LINE   POSITION
TEXT
ATTRIBUTE MESSAGE_NUMBER
SCOTT                          DO_COMMISIONS                  PROCEDURE             1         59      14
PLS-00113: END identifier 'DO_COMMISSIONS' must match 'DO_COMMISIONS' at line 1, column 11
ERROR                113