It always makes me chuckle when I see something like this from a Microsoft site:
Active Server Pages error 'ASP 0131'
Disallowed Parent Path
/downloads/Default.asp, line 15
The Include file '../downloads.html' cannot contain '..' to indicate the parent directory.
which is what just happened when I clicked on the downloads link on the ArcReady site. ( I was looking for the slides after reading Andy Erickson's excellent summary.) Now who knows if someone at Microsoft maintains this site, but after about a million recent security presentations on how you shouldn't leak this kind of error information, it's amusing when it arises. I guess the good news is that they have disallowed parent paths.