Calendar hangs when selecting Exchange account in preferences

I have an Exchange account set up for a company I have just left. So I'm trying to remove that Exchange account from Calendar. When I open Preferences, and go to Accounts, everything's fine, but as soon as I select the Exchange account in the list, Calendar hangs. I'm not sure how I can remove this account.

The hang report is at the following link: http://tyznik.com/misc/Calendar_2012-10-31-140401_Michaels-MacBook-Pro.hang