i got this error after clicking update setting under authentication settings

DotNetNuke.Services.Exceptions.ModuleLoadException: Object reference not set to an instance of an object. ---> System.NullReferenceException: Object reference not set to an instance of an object. at DotNetNuke.Authentication.ActiveDirectory.ADSI.Utilities.AddADSIPath(String Path, Path ADSIPath) at DotNetNuke.Authentication.ActiveDirectory.ADSI.Utilities.GetRootEntry(Path ADSIPath) at DotNetNuke.Authentication.ActiveDirectory.ADSI.ADSIProvider.GetNetworkStatus() at DotNetNuke.Authentication.ActiveDirectory.Settings.UpdateSettings() --- End of inner exception stack trace ---

help

here's what i have now after changing impersonation

 
            <identity impersonate="true" userName="COMP\Administrator" password="pass2009"/>
    <!--
            <authentication mode="Windows">
            </authentication>
 

after loading the portal gives me - "This site is Unavailable" error

what am I missing?

I am having the same issue. I am doing all this in windows xp. I gave FULL permissions to ASPNET in my DNN install I also added myself and did the same thing.  I tried changing <identity impersonate="true" username="STLMSD\myusername" password="xxxxx"/> but it will give me Parser Error Message: Unrecognized attribute 'username'. Note that attribute names are case-sensitive. And I have tried all kinds of variations. 

<identity impersonate="true" username="STLMSD\myusername" password="xxxxx"/>--> and I get to the login screen fine but of course won't authenticate"

And I know I have access to the AD because I was able to set it up and query it using another CMS.

Or can you point me where I can find that part about impersonation in the documentation?
Please help . Thanks!

<!--<authentication mode="forms">

<forms name=".DOTNETNUKE" protection="All" timeout="60" cookieless="UseCookies" />

</authentication>