I'm having the same problem.
It worked at first, but now I can't move the widget to the sidebar in the admin page - it crashes and it creates a lot of copies in the widgets page. When I had it in the sidebar I could not open the appearence boxes either.
I tried different browsers. Using the newest Wordpress. I have a lot of authors on the site.
Anyone else with this problem.
Please help, it's a great plugin.