Quibbler - I'm not quite sure what you mean by the content in side blocks... Could you maybe give me an example of what you're talking about?
I'm honestly not too familiar with the way the referrer system works since that's not something I use. I'm pretty sure though that as long as the visitor uses the link containing "referrerid=X" when they first visit your site that everything will still work. I know a visitor can visit the site, browse threads, and then sign up, so it shouldn't be a problem if they visit other parts as well. It may not hurt to test it out though.
SnowBot - Ok, I figured that was it. I assume you saw that the zip file was updated earlier today, so if you download that and re-apply the file change to functions_calendar.php it should fix the problem.