EventCalendar3 problems

I am using EventCalendar 3. Is it possible to make an event on the
calendar without having to make a blog post? I tried to make one with
a private post so that no one would see it but the event didn’t pop up
on the calendar. I’m inputting all the information correctly but it
just doesn’t seem to work.

Also I am getting the error “Cannot load widgets/widgets.php” – what
does this mean?

I’d appreciate a step-by-step solution to both of these issues. Thanks!