Can't view page on Vista with IIS7

I'm running Vista with IIS7.  When I try to view my site at http://192.168.0.3:81/index.aspx, I get this error:

HTTP Error 500.19 - Internal Server Error
The requested page cannot be accessed because the related configuration data for the page is invalid. Detailed Error InformationModule IIS Web Core
Notification BeginRequest
Handler Not yet determined
Error Code 0x80070021
Config Error This configuration section cannot be used at this path. This happens when the section is locked at a parent level. Locking is either by default (overrideModeDefault="Deny"), or set explicitly by a location tag with overrideMode="Deny" or the legacy allowOverride="false".  
Config File \\?\C:\Dev\www\mysite\web.config
Requested URL http://192.168.0.3:81/index.aspx 
Physical Path C:\Dev\www\mysite\index.aspx
Logon Method Not yet determined
Logon User Not yet determined
 Config Source
  110:                   <add name="ScriptModule" preCondition="managedHandler" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/></modules>
  111:             <handlers>
  112:                   <remove name="WebServiceHandlerFactory-Integrated"/>

I followed the more information link to this site http://support.microsoft.com/kb/942055/, which didn't help. IIS_IUSRS has read permission on the web.config and the entire website folder with subfolders.  Any ideas?