A plea out to all those who are using ASP.NET AJAX with sites on IIS7, either under Vista or Longhorn Server: I've been battling a strange issue with ASP.NET AJAX on IIS 7 running under Vista. It's a site that was upgraded from RC1 to RTM, and works great under IIS 6. Have troubleshot it enough under IIS 7 to determine that if the AppPool has the Managed Pipeline Mode set to "Integrated", it fails, and if it's set to "Classic", it works perfectly. The error I'm getting is one that was common during...