Why every time I receive a calendar invitation my iCal crashes?

Every time I receive a calendar invitation, even if I don't open it, iCal will automatically schedule that as an appointment. The time set up though will be shown as a grey color and I cannot make any change, or even access it. On top of it, if I try to access that day, when I am viewing my calendar as a day (day, week, month...) iCal will definatelly crash and when I try to re launch it will open but I would not be able to see that day in day view again.

To solve the problem I need to go to my iCal on my MAC and reject the invitation. Only then my calendar either in my iPhone or iPad will relaunch properly.

Such a pain.