layout problem: 'previous' and 'next' navigation

I’ve very nearly finished work on my blog, but I have a minor layout problem that I can’t seem to work out how to resolve.

For a typical post, like this one, you’ll see the ‘previous’ and ‘next’ labels at the top right of the post. These display OK in Chrome and Firefox, but in IE they’re pushed over to the right of the sidebar. One of the sidebar widgets appears broken in IE too, and I’m not sure whether this may be related. Any insight would be much appreciated. Thanks.