#Net v1.5 : Auto-attach to process aspnet_wp.exe on machine xxxxxxx failed. Error code 0x8013134b.
Simple. You've installed .NET Framework 2.0, and as by default IIS assigns new virtual directories and websites the ASP.NET 2.0 runtime, when you try to debug the 1.1 web app it gives an error.
Check your website settings at IIS and change the framework version to 1.1, and voila, fixed!