Try setting up another admin user account to see if the same problem continues. If Back-to-My Mac is selected in System Preferences, the Guest account will not work.
If the problem is still there, try booting into the Safe Mode. Shut down the computer and then power it back up. Immediately after hearing the startup chime, hold down the shift key and continue to hold it until the gray Apple icon and a progress bar appear. The boot up is significantly slower than normal.
Thanks to John Maisey of London for resolving this issue. When installing upgrade to 10.8.2 the installation must have broken which card is my card in Contacts.
I did the simple making "this my card" and no resolved this problem Thanks again JM !
The Calendar doesn't know which is your card unless you tell it.
Open Contacts, select your card and choose the menu Card > Make This My Card.
Had same problem ... this fixed it. I agree with Ron, Apple must be more careful to stick to the original design goals. If the application needs you to set a card, the message you get should be explicit adn tell you how to do it. Better yet, test the upgrade that deleted the "My Card" indication before releasing the code.