The instructions are kind of sparse. Delete everything except for App_Data\Settings.txt and App_Data\InstalledPlugins.txt.
But the file structure is completely different in 4.0 and now it is saying that a default doc is not found:
HTTP Error 403.14 - Forbidden
The Web server is configured to not list the contents of this directory.
Detailed Error Information
Module
DirectoryListingModule
Notification
ExecuteRequestHandler
Handler
StaticFile
Error Code
0x00000000
Requested URL
http://localhost:80/
Physical Path
C:\inetpub\wwwroot
Logon Method
Anonymous
Logon User
Anonymous
Most likely causes: •A default document is not configured for the requested URL, and directory browsing is not enabled on the server.