Hi Mark, as before I can’t see this issue.
I can visit the homepage of your site using IE8 and I don’t have any problems doing so – I don’t see any Javascript issues either, the only problems I can see are some viewport issues (see http://pastebin.com/Sqc7kUUV – not Events Calendar related though).
Can you be a bit more specific in terms of describing the sort of trouble your office staff are having in loading your front page? Are they seeing warnings, or are they unable to navigate across the site? I’d need some more detail to be able to help here.