So here’s what’s strange:
1) The top of your button is about 345px from the top of it’s parent div, but your "TOP" is 299px.
2) If you use Firebug to hover over the element, you will see that the #RegisterButton is sitting above where it should be, yet the link "inside" of it is being pushed below it.
Something is pushing that link down ~46px, but it is too late for me to figure out. Anyone have an idea?