Tried twice and got the same error.   Folder permissions, iis and database all seem to be set correctly.  Did not get this on installing earlier 6.2 beta.

Server Error in '/dnndev_6200' Application.

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Unable to load default file registration provider

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Configuration.Provider.ProviderException: Unable to load default file registration provider

Source Error:

Stack Trace:

[ProviderException: Unable to load default file registration provider] ClientDependency.Core.Config.ClientDependencySettings.LoadProviders(ClientDependencySection section, HttpContextBase http) +1350 ClientDependency.Core.Config.ClientDependencySettings.get_Instance() +105 ClientDependency.Core.Module.ClientDependencyModule.LoadFilterTypes() +35 System.Web.HttpApplication.InitModulesCommon() +124 System.Web.HttpApplication.InitInternal(HttpContext context, HttpApplicationState state, MethodInfo[] handlers) +1655 System.Web.HttpApplicationFactory.GetNormalApplicationInstance(HttpContext context) +374 System.Web.HttpApplicationFactory.GetApplicationInstance(HttpContext context) +178 System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr) +371

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.225

Hi.
I've the same problem in Windows 7 x64 with UAC enabled.

The steps:
1) copied dotnetnuke 6.2.0 install version in c:\inetpub\wwwroot
2) renamed folder install in dnn620
3) set all permission to iis apppool\defaultapppool for the folder dnn620 because my app depend on defaultapppool
4) my defaultapppool start in 32bit, classic, net 2 (same error with start at 64bit)
5) run the application
6) select custom installation
7) create database correctly
8) press the next button and the following exception is displayed

The web,config is not read-only and inherits correctly the parent permission.

Server Error in '/dnn620' Application.
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Unable to load default file registration provider
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Configuration.Provider.ProviderException: Unable to load default file registration provider

Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:
[ProviderException: Unable to load default file registration provider]
ClientDependency.Core.Config.ClientDependencySettings.LoadProviders(ClientDependencySection section, HttpContextBase http) +2012
ClientDependency.Core.Config.ClientDependencySettings.get_Instance() +91
ClientDependency.Core.Module.ClientDependencyModule.LoadFilterTypes() +24
System.Web.HttpApplication.InitModulesCommon() +124
System.Web.HttpApplication.InitInternal(HttpContext context, HttpApplicationState state, MethodInfo[] handlers) +1162
System.Web.HttpApplicationFactory.GetNormalApplicationInstance(HttpContext context) +312
System.Web.HttpApplicationFactory.GetApplicationInstance(HttpContext context) +133
System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr) +196
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Version Information: Microsoft .NET Framework Version:2.0.50727.5456; ASP.NET Version:2.0.50727.5456

Whit your informations I've checked the web.config.
The web.config is ok. and contains dozen of clientdependency, created by wizard.
In the app_data\clientdependency the xml was created by wizard. The name of xml start with the name of computer (no DNS name).

The Windows 7 are in domain with dynamic IP and UAC enabled.
The DHCP do not respond to netbios.

Then I've:
1) disabled the UAC
2) enabled netbios over tcp/ip
3) disabled IPv6
4) restarted the computer

Now the wizard has worked and the website render is ok.

Thank you.