Jason
Extract from a previous post in this ng:
The _vti_ directories and their files are system files used by FrontPage and
work in conjunction with the server-based extensions.
They are necessary if you have extensions installed for use by your site,
and not necessary if you don't have the extensions installed for use by your
site. Any questions about whether the extensions are installed should be
directed to your hosting company technical support.
Hope this is useful.
Rob