I've got what may be a stupid question.  I've installed DNN before(using sql server 2000), and I'm now trying to get DNN running with SQL server express 2005. 

I've followed the instructions on setting up DNN with a SQL server express 2005 database, but when I try to install the site I get :

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:

Line 72:
Line 73:             'check if this is an "html" file
Line 74:             If Request.Url.LocalPath.ToLower.EndsWith(".html") Then
Line 75:                 Exit Sub
Line 76:             End If 

Source File: c:\inetpub\wwwroot\dnn\App_Code\Global.asax.vb    Line: 74

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.]
   System.Web.Hosting.ISAPIWorkerRequestInProc.GetServerVariable(String name) +1132
   System.Web.Hosting.ISAPIWorkerRequest.GetServerName() +15
   System.Web.HttpRequest.get_Url() +282
   DotNetNuke.Common.Global.CheckVersion() in c:\inetpub\wwwroot\dnn\App_Code\Global.asax.vb:74
   DotNetNuke.Common.Global.Application_Start(Object Sender, EventArgs E) in c:\inetpub\wwwroot\dnn\App_Code\Global.asax.vb:263

 
Any Help would be appreciated.