I just changed from forms to windows authentication. Same error.

>There's also an option to set forms or windows authentication... you may wish to try windows....
>
>
>>I should have mentioned that, it is already set to true.
>>
>>>There is an option in the web.config file that you must set to true: (here is from mine)
>>>

>>>     <!-- set debugmode to false for running application -->
>>>	     <compilation debug="true" />
>>>     <!-- permits errors to be displayed for remote clients -->
>>>	     <customErrors mode="RemoteOnly" />
>>>     <!-- Forms or Windows authentication -->
>>>	<authentication mode="Forms">
>>>	     <forms name=".DOTNETNUKE" protection="All" timeout="60" />
>>>	</authentication>
>>>     <!--
>>>

>>>
>>>Hope this helps.