trouble syncing google calender on iCal

Hi there,

I usegoogle calender, but when I want to add an iCal account with my google account, it gives this notification. And does not sync.

(in English: The server responded with a Error.

https://calendar.google.com/calendar/dav/boris.kesber@gmail.com/user///calendar.google.com/calendar/dav/boris.kesber@gmail.com/user/

is not a location that supports this request)

Any help?