Hello,
Just to totally clear, you mention this above:
using Version 3.9.2 PRO
Do you mean that you are literally using version 3.9.2 of Events Calendar PRO on your site?
This isn’t necessarily a problem, but 3.9.2 is somewhat outdated, and if you are using a more recent version of The Events Calendar core on your site, the mismatching version numbers could lead to the sorts of issues like you’re describing with the list widget.
So, there are two things I’d recommend looking into here:
1. First, if you simply drag a “real” List Widget to a sidebar in the Appearance > Widgets area of your site, does that instance of the List Widget work fine? Or does it fail just like when you try to call it via shortcode?
2. If possible, can you try ensuring that both The Events Calendar and Events Calendar PRO are updated to 3.10.1 on your site? You can get the PRO files at http://theeventscalendar.com/my-account/downloads, and the Core files at http://wordpress.org/plugins/the-events-calendar
Thank you!
George