[jQuery] Animating background color

[Apothem]

I use jQuery 1.3.2 and tried to use:
                $('.applied').each(function(){
                        $(this).css('background-color', '#ff0000').animate
({backgroundColor: "#000" }, "slow");
                });

For some reason, the background doesn't change and my firefox debugs
the error of "NaNpx" a few times. What is wrong?