A critical error has occurred.
Failed to load v13wstat3. The control tree into which v13wstat3 is being loaded must match the control tree that was used to save v13wstat3 during the previous request. For example, when adding controls dynamically, the controls added during a post-back must match the type and position of the controls added during the initial request.

I installed the new Events module.  I imported the AVCalendar events.  I had to manually copy over the categories, locations etc from the calendar tables, but this was not difficult.

I am getting an occasional v13wstat3 error though.  I cleared the cache, turned off the blowery compression module and I was still getting the errors.  To recreate, try editting an event, Save.  Now navigate to a different page, now come back to your Events page.  This doesn't happen every time, but it happens enough to make me think something is going on here.