This post — http://dotnet.org.za/armand/archive/2005/07/03/38757.aspx — saved me from spontaneous, self-inflicted baldness.
I’ve been updating www.benday.com over the last few days and for about 4 hours this afternoon it was totally dead. Any aspx page that I tried to execute would come up as “404 – Resource cannot be found” even though the file was definitely there.
Turns out that there’s a special file named “app_offline.htm” that will torpedo your web app just by being in the directory. I’m not sure where this file came from but it was in my web directory and had 0 bytes in it. Deleted that file and everything’s back to normal.