配置错误cofig error

ASK:
I dont understand the solution which was:

 Parser Error Message: It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level.  This error can be caused by a virtual directory not being configured as an application in IIS.

Can someone explain what this message means please?

BEST ANSWER:

We encounter that error when matching one of the following conditions (the web.config should contains the sections that registered as allowDefinition='MachineToApplication'):

    1. Have web.config in the sub-directory of the web application.
    2. Current web project has not been configured as virtual directory/web application in IIS.
    3. The specified section, such as “authentication” exists in the “location” Element.
    4. Open the parent directory of the web project in Visual Studio via "File | Open | Web Site...", and lauch it in ASP.NET Development Server.

For more information, please refer to the following link:

section Element for configSections (General Settings Schema)
http://msdn.microsoft.com/en-us/library/ms228245.aspx

location Element (ASP.NET Settings Schema)
http://msdn.microsoft.com/en-us/library/b6x6shw7.aspx

How to: Create and Configure Virtual Directories in IIS 5.0 and 6.0
http://msdn.microsoft.com/en-us/library/zwk103ab.aspx