I assume you imported an MC9 library to MC14.
The internal playlists are automatically kept in sync with the media files. Possibly the media files are not in exactly the same place and MC14 has imported them as new files. If that happened the playlists are empty because the old files do not exist in the library anymore.
Cold you provide more information? Did you move the files, did a drive letter change, do you use a different Windows user account, do you use a different OS or PC, etc ?
If you still have a backup copy of the MC9 library it may be possible to mass change the filename paths inside the library.