regarding an error in pl/sql procedure

Hi,
I am getting the error ora-29280 in my procedure while reading data from the file...Its showing invalid directory path....Basically what all I need for a directory i mean permissions and where should I place my file???I am pasting my procedure..please check it out...Thanks


CREATE OR REPLACE PROCEDURE exdept is
fhandler utl_file.file_type;
nextline varchar2(100);
num2 number(10);
num1 number(10);
num number(10);
i number(10):= 1;
cnt number(10):= 1;
txt_file varchar2(100):='deptno.txt';
BEGIN
fhandler :=utl_file.fopen('C:\Program Files\Oracle',txt_file,'R');
if utl_file.is_open(fhandler) then
loop
begin
utl_file.get_line(fhandler,nextline);
if nextline is null then
exit;
end if;
begin
execute immediate 'insert into depart(deptid) values(nextline)';
end;
end;
end loop;
end if;
utl_file.fclose(fhandler);
execute immediate 'insert into depart(seq) values(i)';
while i>0
loop
begin
select deptid into num from depart where rownum=i;
if num is null then
exit;
end if;
select deptid into num1 from depart where rownum=i;
select deptid into num2 from depart where rownum=i+1;
if num1=num2 then
cnt:=cnt+1;
execute immediate 'update depart set seq=cnt where rownum=i';
else
cnt:=1;
execute immediate 'update depart set seq=cnt where rownum=i+1';
end if;
end;
i:=i+1;
end loop;
END;
/