I'm so close to getting Rails working on IIS-5.1 on WinXP-SP2... I've done everything you describe here, and after many fits and starts, IIS is at least talking to my rails app. Sadly, it's getting an 500 Application error from rails when I make what would appear to be valid requests of my app.

Yes, everything works fine in webrick. Note that when I run ruby dispatch.fcgi from the command-line, I also get a 500 Application error.

Can you suggest a possible route of attack to debug this problem?