Why should I comment the following lines in my webconfig in order to work in IIS ?

Question

I'm new to IIS 7.5 (Window 7)

If while I new ASP.NET 3.5 Website target it on Local IIS , it works without any problem . But if i new a file-system ASP.NET 3.5 Website and from IIS add that website and configure it , It doesn't work . I get this error

In order to work I had to comment these following lines

<sectionGroup name="system.web.extensions" type="System.Web.Configuration.SystemWebExtensionsSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
        <sectionGroup name="scripting" type="System.Web.Configuration.ScriptingSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
          <!--<section name="scriptResourceHandler" type="System.Web.Configuration.ScriptingScriptResourceHandlerSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>-->
          <sectionGroup name="webServices" type="System.Web.Configuration.ScriptingWebServicesSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
            <!--<section name="jsonSerialization" type="System.Web.Configuration.ScriptingJsonSerializationSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="Everywhere" />-->
            <!--<section name="profileService" type="System.Web.Configuration.ScriptingProfileServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication" />-->
            <!--<section name="authenticationService" type="System.Web.Configuration.ScriptingAuthenticationServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication" />-->
            <!--<section name="roleService" type="System.Web.Configuration.ScriptingRoleServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication" />-->
          </sectionGroup>
        </sectionGroup>
      </sectionGroup>

I'm wondering why should i comment those lines while it isn't necessary for the first way?

Thank you

Edit :

When i say First way , I mean when creating a webiste , I chose "Http" instead of "File System" in Weblocation drop downlist . and target it on IIS not webserver provided with Visual Studio

Answer 1

As the error states, it is because they are duplicate (the same tags are defined somewhere else aswell). It could either be that they are already somewhere else in your own file, which is probably not so likely, or they could also be in machine.config, or in another web.config file in a parent folder.