Have you cleared the events for the time period you're reporting on? If so click 'Show Cleared Events' tick box and try again.
Failing that, do you get any results if you change the Event Type to 'All events'?
Have you cleared the events for the time period you're reporting on? If so click 'Show Cleared Events' tick box and try again.
Failing that, do you get any results if you change the Event Type to 'All events'?