Getting ORA-06502 error..Pls Help

[sabita_ban]

I have a procedure block as given below...
I am getting the above error for the line

Comp_list := Comp_list || CompId || ',' ;

Comp_list is of VARCHAR2(1000),CompId is of type NUMBER(10)...

Please help me out on this...I need to prepare a comma seperated list of numbers but am failing to do so..


DECLARE
CURSOR C2 IS SELECT NAME_ID FROM RPTDEFN WHERE RPTNAME=Report_Name;
BEGIN
OPEN C2;

n :=1;
Comp_list :='';

LOOP
FETCH C2 INTO CompId;

IF n=Comp_Counter THEN
Comp_list := Comp_list || CompId ;
ELSE
Comp_list := Comp_list || CompId || ',' ;
END IF;


n := n+1;

END LOOP;

CLOSE C2;
END;