While testing on IE9 I get an error message for the mini calendar "Error displaying the error page: Invalid URI detected." It works fine in Chrome & Firefox, but unfortunately I need it to work in IE still because I have clients that use it.
Also - is there a way to just show an event, but not allow people to register for it. My clients have classes to register for and events shown as courtesy.
Don't know about the IE9 problem, but the way I have set up events and not allow registration is to set the Registration Open Date to a date after the event finishes.