shortcode filter for category not working 1.9.1

I am trying to use the shortcode to show events on the calendar that are in a particular category (and only that category). I’ve tried using the name, the slug and the id, and with either of these, I still see all events in the calendar (month view by default).
[ai1ec cat_name="halloween"]
I am using version 1.9.1
The WordPress version is 3.3.1
Since this version of the plugin isn’t on wordpress.org yet, I can’t see version compatibility info, and I’ve looked at the timely site, which doesn’t mention it. Perhaps I need a more recent version of WP? I hesitate to update to 3.5 because I have heard a lot of issues being brought up on some forums.
I am also using a child theme of Thematic…only slight changes have been made within the child theme. It’s mostly just styling.
Please advise.

http://wordpress.org/extend/plugins/all-in-one-event-calendar/