Address Book Corrupted

One night, my Address Book suddenly disappeared. I fired up Time Machine, found my most recent backup, and clicked restore. I was asked if i was sure I wanted to Restore X number of contacts, I clicked yes. The cards appeared in the Address Book window, but it then locked up. So I had to force quit it. When I reopened Address Book, it was empty again. The same thing happens if I just try and add a single contact from Time Machine.

I also can't add Contacts manually - if I do, once I click 'edit' again to go back to the normal screen, it goes all weird, like this: