IIS Express Duplicate section defined in 'system.web.extensions/scripting/scriptResourceHandler'

Try to delete sites with the same port in IIS Express configuration file located in you user folder

C:\Users{USER_NAME}\Documents\IISExpress\config\applicationhost.config

<listenerAdapters>
    <add name="http" />
</listenerAdapters>

<sites>
    <site name="orchard" id="10">
        <application path="/" applicationPool="Clr4IntegratedAppPool">
            <virtualDirectory path="/" physicalPath="C:\Users\{USER_NAME}\Documents\My Web Sites\orchard" />
        </application>
        <bindings>
            <binding protocol="http" bindingInformation="*:3473:localhost" />
        </bindings>
    </site>
    <site name="Pacotes" id="29">
        <application path="/" applicationPool="Clr4IntegratedAppPool">
            <virtualDirectory path="/" physicalPath="D:\svn\comuns\develop-v1.7.2-Scripts\Nuget.Server" />
        </application>
        <bindings>
            <binding protocol="http" bindingInformation="*:55004:localhost" />
        </bindings>
    </site>
</sites>

<webLimits />