Looks fine in FireFox, but its definitely not getting along well with IE.
It wouldn't be something you could fix in your own personal installation of IE. The skin templates would have to be changed in order to accomodate IE's.. quirks..
IE likes to have table cells share the available column width equally unless told specifically otherwise, while Firefox will, more appropriately, allow the right-most cell to consume the remaining available space after the other cells have taken only what they need. Some simple editing of the tables used to generate the forum's pages can correct the issue simply enough, but it is technically a quirk of IE, not a bug in the skin's templates.
And for the record, I like the new skin.