Am using Zorin OS 5.2, essentially Ubuntu 11.04 I think. If I attempt to delete all old events skype crashes from the desktop and I have to sign in again. I can delete one event without a problem but when I delete the final event that is left, then it crashes. Even if you try to delete events, they are not deleted and return when you log in again. Strange.
Indeed it is a bug.
A workaround has been posted at the end of this ticket:
We apologize for this.