Wordpress plugin settings do not work with IE9. I’ve provided more details in the Joomla / WP threads. Quick description is that IE9 now supports implementation.createDocument. Scheduler code assumed that IE would never support this and trys to use an unsupported method (“load”) on the resulting xml doc created. See proof below.
Yep, we really have missed it. While public part was updated to work in IE9, code which is used in admin part was not updated. We will include fix in the next version. Thanks for provided info.