Asp.net Website Adiministration Tool Security setup wizard

Hi
I am using VS 2008 and Windows 7 as operating system.I am trying run Security setup wizard .I  am getting the following error while doing that.
The following message may help in diagnosing the problem: Specified argument was out of the range of valid values. Parameter name: site at System.Web.Configuration.WebConfigurationHost.InitForConfiguration(String& locationSubPath, String& configPath, String& locationConfigPath, IInternalConfigRoot configRoot, Object[] hostInitConfigurationParams) at System.Configuration.Configuration..ctor(String locationSubPath, Type typeConfigHost, Object[] hostInitConfigurationParams) at System.Configuration.Internal.InternalConfigConfigurationFactory.System.Configuration.Internal.IInternalConfigConfigurationFactory.Create(Type typeConfigHost, Object[] hostInitConfigurationParams) at System.Web.Configuration.WebConfigura ...