Ooo, this is a fiddly little so-and-so. Finished putting together all the blocks for the site, all ready to get on with the work that I'm supposed to be doing only to discover that Internet Explorer is throwing an absolutely fit. Tried loading the page in a bunch of different IE versions to discover the same thing.

Internet Explorer cannot open the Internet site.
Operation aborted.

Trying to navigate to another page results in another error, something like:

Internet Explorer is trying to load this page. Are you sure you want to navigate away?

Turns out, it's an IE-specifc error relating to Javascript. After a bit of trial and error, removing and adding back in various widgets, it turns out the one I'm using to display the latest Twitter action is the offender. The fix is to add:

defer="defer"

into the Javascript call, so it becomes:

<script type="text/javascript" src="http://twitter.com/javascripts/blogger.js" defer="defer"></script>
<script text="text/javascript" src="http://twitter.com/..." defer="defer"></script>