This sounds like an issue with the Windows Messenging System Address Book Service Profiles.
I should point out that Formativ does not modify (or even use) the Windows messenging system services in any way. Installing Formativ does not modify any messenging components. However, installing Outook and/or Outlook Express can upset the profiles, which can manifest issues with address books.
Just to clarify, the Outlook migration applet (which I assume you are using?) only works with the full Outlook client – Outlook Express is not supported in any way whatsoever. I could not predict the applet behavior when used with Outlook Express.
When you say “your address book became completely empty and almost vanished”, which address book are you referring to? Your system address book? A personal address book you attempted to import Outlook contacts from?
I would suggest you backup your PST file, then uninstall all Outlook clients (Outlook and Express) from the PC. This will hopefully restore the messenging system services back to a stable state.
Please let me know how you proceed.