ASP.NET: Object Reference not set to an instance of an object.

I encountered the folliwing error when trying to run a web site hosted under the IIS in anew machine. Basically in order to solve the problem, run aspnet_regiis -i to install ASP.NET 2.0.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.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:
[NullReferenceException: Object reference not set to an instance of an object.] System.Web.Hosting.ISAPIWorkerRequestInProc.GetServerVariable(String name) +1618 System.Web.Security.WindowsAuthenticationModule.OnEnter(Object source, EventArgs eventArgs) +593 System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +92 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +64