Your plugin is really cool but I think quite young :)
When wordpress is installed in a subfolder like http://mywebsite.org/folder/ all the places shows a 404 page when pointing to the permalink. Eveything is ok with events.
Although, some improvement could be :
- using leaflet (openstreemap) instead of google map
- add a town field in places (to get it separatly in templates)
- separate date and hours fields in the mediabox of an event (the current is not really intuitive).
It's just advices :) Sorry I've no time for now to patch your code. Hope you'll get time for this.