I have been using the free version for more than a year with AOL 8 and Win XP and my address book has never wiped out and I have loads of names in it. I would uninstall and then download and install the program again and see if that helps.
My incredimail address book keeps wiping itself clean. Every time I close the program, all the address book info disappears and I have to re-import. Is this a "feature" of the free, ad supported version? Their technical support seems to be nonexistent. Using WinXP.