Importing addressbook to Outlook 2000

I am in the process of migrating a user from netscape to outlook2000. When I back up their addressbook, it’s saved as a .ldif file, but Outlook doesn’t recognize it. I’ve tried to save it in other forms, but when I try to import it, I can’t find it. When I go back to the folder it’s in on the network, the addressbook is there. What am I doing wrong?