<div id="blanksideboxContent" class=".sideBoxContent">
<a href="#">this is a link</a>
You defined "color:black;" for the font, so you need to befine a color other than black for the border., else you are using black for both 'edges' of the outset style. Remember, the font-color here is probably the assumed color for border, unless explicitely stated otherwise.
If you look very, very closely, there IS a slight difference in the border-edges when using black-black... it is very sublime. IE probably incorrectly 'assumes' you meant something else, and 'fauxes' the outer or inner edge to show what you intended to do.
I also changed your ID and CLASS... they may have been right but they made no sence to me, and what I did, works.