This error occurs when a document is not specified in the URL, no default document is specified for the website or application, and "directory listing" is not enabled for the website or application. This setting may be disabled to secure the contents of the server.

This becomes an issue when not all aspnet features have been installed or registered. The user must make sure that the needed aspnet features were checked in (turn windows features on and off) and that they ran aspnet_regiis.exe as an admin in the v4 folder (C:\WINDOWS\Microsoft.Net\Framework\v4.0.30319\aspnet_regiis.exe).