Yosemite Calendar v8: "You don’t have permission to modify this event."

[JohnDohe]

I'm getting this message when I right-click on a day in Calendar version 8.0
and select "New event":
     "You don’t have permission to modify this event."
     "The owner of this calendar doesn't allow you to create these items."

(please see attached Screen Shot 2015-04-29 at 9.35.06 PM   Wednesday  4-29-15.png)

What to do?

HALP !!!

[attachment deleted by admin to conserve space]

[Geek-9pm]

Are you the one who entered the event?
Can you enter a new event?
I see you also posted this on another forum.
Almost a year ago? No solution?

The workaround is to stop using it and get another Calendar application.
Best Calendar Apps and Utilities for Mac
That's all I can tell you.