if i use:

<style type=text/css>
body
{
scrollbar-face-color: #FFFFFF;
scrollbar-track-color: #FFFFFF;
scrollbar-face-color: #FFFFFF;
scrollbar-shadow-color: #FFFFFF;
scrollbar-highlight-color: #FFFFFF;
scrollbar-3dlight-color: #FFFFFF;
scrollbar-darkshadow-color: #FFFFFF;
scrollbar-arrow-color: #AFEEEE;"}
</style>

on a layout, the white parts of the scrollbar come up also - how can i get only the colored arrows to show up?

As far as I know, you cannot get rid of the white track color on a scrollbar. On sites outside of Neopets, you can use scripts for transparent scrollbars, but they do not allow these on Neopets.