What does .FBCIndex File do?

When I run backup on my 2003 Server, it hangs on this .FBCIndex file. I found limited information on this (which is created when a user uses Finder, creating an index of the directory being searched?). Is this a permanant file? The file is sitting in the root directory of the Mac share volume (so is it an index file for the entire Mac share?). Does the system delete it and recreate it? Any info would be greatly appreciated.

I did some poking around and found vulnerability reports related to these files (mind you they are dated back to 2001):

http://www.securityfocus.com/bid/3325/info

it appears to have been addressed and still cannot find much info on these files - have you since found info to share with us?