The Revert to Address Book Backup feature opens a backup file created by the Address Book backup feature only.
I'm not sure if any of these files can be used to restore the data but I've got something for you to try.
Why do the the contacts get erased from the iPhone if the computer's address book is empty? Is this a feature or a bug? Seems like a bug.
I don't believe this is a bug - kind of like which was last changed prior to the sync process - in this case if was your Address Book database on your Mac. If there had been at least one contact available on the Address Book on your Mac, I don't believe this would have occurred but since it was empty and the last changed all contacts were lost on the iPhone.
With the Address Book application quit on your Mac, move the recovered AddressBook.data.previous file from the backup drive to the Desktop. Change the name of this file to AddressBook.data or remove .previous from the file name.
Using the Finder, go to Home > Library > Application Support > AddressBook. Move the AddressBook.data file from the Desktop within the AddressBook folder. This will replace the existing AddressBook.data file which is empty.
Cross your finger and then launch the Address Book application to see if most or all of your Address Book contacts were restored.