I want to change the colour of the drop down arrow of my dropdown menu to match this:
<style type="text/css">

BODY
{
scrollbar-face-color: #E4B7F5;
scrollbar-highlight-color: #FFFFFF;
scrollbar-3dlight-color: #EFD6F8;
scrollbar-darkshadow-color: #D994F2;
scrollbar-shadow-color: #DEA4F4;
scrollbar-arrow-color: #FFFFFF;
scrollbar-track-color: #EFD6F8;
}
</style>

And i also want to change the border of my frames with css

You can't change the colour of the drop down arrow.

For the frames thing you could try this
<style type="text/css">
frame { border: 1px solid #000000 }
</style>
(or use iframe instead if it's not a regular frame)