SQL Server 2000 - Which part of the code line generates error in the below user-defined function?

CREATE FUNCTION [dbo].[SampleFunction]
RETURNS DATETIME
AS
BEGIN
DECLARE @TodaysDate DATETIME
SET @TodaysDate = GETDATE()
SET @TodaysDate = DATEADD(DD, DATEDIFF(DD, 0, @TodaysDate), 0)

RETURN @TodaysDate
END