Admin Widget Area loads Slowly with plugin installed

With the plugin installed, going to Appearance > Widgets takes over 30 seconds to load. No other admin pages take that long to load. I deactivated the Custom Sidebars Pro plugin, and the widgets page loaded up instantly. This makes it something with the Custom Sidebars Pro plugin. I do have 20 normal widget areas, but not all of them are set to be replaceable (only 3 are marked as replaceable) so I wasn't sure if that had anything to do with it. Any help would be greatly appreciated!