dotnetnuke cant open my page

Am trying to learn how to use dotnetnuke so am kinda new to it. I installed it correctly and i set up a user in server management studio. So when i try to open my page localhost\mypage i get these errors:

HTTP Error 500.19 - Internal Server Error
The requested page cannot be accessed because the related configuration data for the page is invalid.

Detailed Error Information:
Module     IIS Web Core
Notification       Unknown
Handler    Not yet determined
Error Code     0x8007000d
Config Error       Configuration section not allowed in a <location> tag
Config File    \\?\C:\inetpub\wwwroot\ANTONISDB\web.config
Requested URL      http://`localhost`:80/dotnetnuke
Physical Path      
Logon Method       Not yet determined
Logon User     Not yet determined

Config Source:

  210:   </system.web>
  211:   <runtime>
  212:     <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">

Anyone knows whats wrong with this?

Check to make sure the Application Pool for the virtual directory/application is configured to USE ASP.NET 4.0, DNN won't run with .NET 3.5 anymore (starting with Version 7)