RESET COUNTER

Hello everyone:

this procedure resets the business day to one for every month. It works fine except for the month of October. any idea or suggestions?

DECLARE @i INT
SET @i = 1
DECLARE @DateID INT,
@DtTimeD DATETIME,
@LASTDAY DATETIME
DECLARE c CURSOR
FOR
--
-- LASTDAY is the last day of the month
-- the counter will reset to 1 on the first of each month
--
SELECT DateID, DtTimeD, DATEADD(dd, -DAY(DATEADD(m,1,DtTimeD)), DATEADD(m,1,DtTimeD)) 'LASTDAY'
FROM D_DATE
WHERE WkDayIn = 'Yes' AND HolidIn = 'No'
OPEN c
FETCH NEXT FROM c INTO @DateID, @DtTimeD, @LASTDAY
WHILE @@FETCH_STATUS = 0
--
-- update the business day in D_DATE
--
BEGIN
UPDATE D_DATE
SET BusDay = @i
WHERE DateID = @DateID
--
-- reset the counter to 1 if it's the last day of the month
--
IF @DtTimeD = @LASTDAY
SET @i = 1
ELSE
SET @i = @i + 1
--
IF @@ROWCOUNT = 500
COMMIT
--
FETCH NEXT FROM c INTO @DateID, @DtTimeD, @LASTDAY
END
CLOSE c
DEALLOCATE c
GO