IE Spry Menu Bar Problem

I'm a novice webmaster and I'm trying to get my first site off the ground.
However the foundation is crumbling beneath my feet.

On Safari, my Horizontal Spry Menu bar looks magnificent. On FF and IE it
looks slightly off..
When the cursor is hovering over a button, it appears to have a black box to
the left taking up space and the borders are missing.

The URL is http://www.oddlysuggestive.com

Any tips are much appreciated.