thanks to reply.
i think that there is not a data range problem , because
here i m using getdate() for date.
actually when i try following query
>> Select Getdate()
i got result.
but when i try to convert or cast getdate into smalldatetime , so i m facing problem.
>> select cast (getdate() as smalldatetime)
i got error.
i think that its a sqlserver 2005 installation problem. because when i try same query on another sqlserver 2005 ,its working.