[Lynne]

I would guess that every file that vbulletin includes in it's downloads is important in some way. That one has to do with the rss poster though, so maybe if you aren't using that, then you don't need it (you can try renaming it and see what happens). However, what is the real problem here? You should have your admin cp and mod cp htaccess protected and the only people who should be able to get in are people you've given the username/password to.