Can't authenticate as (null).

[Tom Edelbrok]

I'm using Visual Studio 2005 with VB.NET. When I create an ASP.NET web
application under wwwroot on my local machine (ie: at
http://mymachinename.mydomainname.local/mytestwebapp) it works fine until I
set up a SQl data source that points to our SQL server (on a dedicated
Server 2003 machine running SQL Server 2000). At this point I get an error
saying that it can't connect as (null).

Note that if I create my ASP.NET web application on my network share drive
everything works fine. I read on the internet that the problem has to do
with 'only one hop allowed' when using password authentication passthrough.
I tried the stuff about setting my machine in Active Directory to allow
delegate, and also in web.config to allow Kerberos to delegate, but no luck.

What can I do to get rid of this error? Note that when I add the SQL data
source to the web application and click on the 'test' button my bound grid
fills up with data nicely - no problem. It's only when I press F5 to
actually run the application that VS2005 returns the error that a process is
trying to log in as (null).

Thanks for any help,

Tom