SQL & PL/SQL

Hi ,
I'm happy to inform you that I've joined recently in this forum.
And my query is:

The following pl/sql program is giving the above error. Please hint me why it is so

DECLARE
TYPE TYP_DUP1 IS TABLE OF DUP1%ROWTYPE;
V_DUP1 TYP_DUP1;
BEGIN
SELECT A
BULK COLLECT INTO V_DUP1
FROM DUP1;

FOR I IN V_DUP1.FIRST.. V_DUP1.LAST LOOP
DBMS_OUTPUT.PUT_LINE(V_DUP1(I).A);
END LOOP;
END;
/

The error is:
******************************************
declare
*
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error
ORA-06512: at line 6
******************************************

Thanks
Jyothsna