Site Feedback - 'get_toolbar().get_entry().ID' is null or not an object

I get the following error:

Line: 23
Error: 'get_toolbar().get_entry().ID' is null or not an object

When mousing over the "in reply to stevo_" box in this Coffeehouse comment:

http://channel9.msdn.com/forums/Coffeehouse/418483-Midori/?CommentID=419121

The error dialog pops up twice (requires two clicks on No to dismiss).

This is in IE7

Edit: Further investigation reveals that it appears to only happen when I visit the last post of a thread directly by clicking on the time in the thread list, and when the "in reply to" box references a post from a previous page of the thread.