Right click on one of the x images and select properties. This is where ASP.NET is looking for the files. Now check if the folders and files actually exist.
If they exist then the permissions for IIS may be incorrect. Typically ASP.NET uses Network Service which should have full access to the root and child folders of your virtual folder.
If they do not exist then something went wrong during the installation. You may have installed over an existing install, or managed a partial install. In this case the best solution is to start with a fresh database and fresh installation of DotNetNuke.
I hope this is of some help to you.