It’s taken quite some time but I think I found the problem: the internet guest account used by IIS, under which ASP pages run, must be permissioned on the file system not through the Internet Service Manager administrative tool. It seems obvious now.

Two interesting things: First, IIS seems to wholly rewrite its logs with each entry so tailing them is not possible. Tried it with a three implementations of tail and it doesn’t work. It’s as if it copies everything to a new file, unlinks the old one and renames the new one to the old name. Weird. Second, and this is probably in the “Well, duh!” category for Windows developers, is that there is a nice little server-side debugger for these scripts with break points, stack trace, etc. in IIS and if enabled will emit useful information when an exception occurs. Neat.