What software are you using? 2000 or XP. The error below usually is an inidication of the rights issue on the directory.

When I go to properties on my dotnetnuke folder (XP pro), there is a tab called "Security", it is here that I added the asp.net/machine account and set the rights to everything for that user.



>Thank you John. I got farther than ever before. Couple of questions:
>
>1) Regarding the rights to the directory. When you right click on the dotnetnuke folder there is a tab Sharing that has a Network Sharing and Security, and also a tab "Web Sharing" which is set to share on default web site of IIS with alias DotNetNuke, but ther no way to add the asp.net/machine account. Is the Web Sharing setting the equivalent of adding the asp.net/machine account?
>
>2) When I type http:\\localhost\dotnetnuke into the address bar of the browser I get the following error message:
>
>

>Server Error in '/DotNetNuke' Application.
>--------------------------------------------------------------------------------
>
>Object reference not set to an instance of an object.
>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.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.]
>   DotNetNuke.DataProvider.Instance() +243
>   DotNetNuke.Upgrade.AutoUpgrade() +92
>   DotNetNuke.Global.Application_Start(Object Sender, EventArgs E) +157
>--------------------------------------------------------------------------------
>Version Information: Microsoft .NET Framework Version:2.0.40607.16; ASP.NET Version:2.0.40607.16
>

>
>Do you (or anyone else) know how to proceed?
>
>Thank you very much.
>
>Alex