Running PSConfig after sharepoint update errors out at step 5 - cannot write configuration file - applicationHost.config

Have gone through the process of doing PSConfig on 4 or 5 servers now.  This one will not complete the update.  The log entry states.

01/12/2013 10:55:26  9  INF            Creating service connection point for this farm ...
01/12/2013 10:55:26  9  WRN            Failed to add the service connection point for this farm
01/12/2013 10:55:26  9  INF            Entering function StringResourceManager.GetResourceString
01/12/2013 10:55:26  9  INF              Resource id to be retrieved is ServiceConnectionPointNotCreatedEventLog for language English (United States)
01/12/2013 10:55:26  9  INF              Resource retrieved id ServiceConnectionPointNotCreatedEventLog is Unable to create a Service Connection Point in the current Active Directory domain. Verify that the SharePoint container exists in the current domain and that you have rights to write to it.
01/12/2013 10:55:26  9  INF            Leaving function StringResourceManager.GetResourceString
01/12/2013 10:55:26  9  WRN            Unable to create a Service Connection Point in the current Active Directory domain. Verify that the SharePoint container exists in the current domain and that you have rights to write to it.
Microsoft.SharePoint.SPException: The object LDAP://CN=Microsoft SharePoint Products,CN=System,DC=sec,DC=local doesn't exist in the directory.
   at Microsoft.SharePoint.Administration.SPServiceConnectionPoint.Ensure(String serviceBindingInformation)
   at Microsoft.SharePoint.PostSetupConfiguration.UpgradeTask.Run()
01/12/2013 10:55:35  9  ERR            Task upgrade has failed with an unknown exception 
01/12/2013 10:55:35  9  ERR            Exception: Microsoft.SharePoint.Upgrade.SPUpgradeException: Action 4.0.14.0 of Microsoft.SharePoint.Upgrade.SPIisWebSiteWssSequence failed. ---> System.Runtime.InteropServices.COMException (0x80071A91): Filename: \\?\C:\Windows\system32\inetsrv\config\applicationHost.config
Error: Cannot write configuration file
   at Microsoft.Web.Administration.Interop.AppHostWritableAdminManager.CommitChanges()
   at Microsoft.Web.Administration.Configuration.CommitChanges()
   at Microsoft.Web.Administration.ConfigurationManager.CommitChanges()
   at Microsoft.Web.Administration.ServerManager.CommitChanges()
   at Microsoft.SharePoint.Administration.SPIisServerManager.CommitChanges(ApplyChanges applyChanges)
   at Microsoft.SharePoint.Upgrade.EnableIIS7IntegratedMode.Upgrade()
   at Microsoft.SharePoint.Upgrade.SPActionSequence.Upgrade()
   --- End of inner exception stack trace ---

and ....

01/12/2013 10:55:35  9  INF                Entering function StringResourceManager.GetResourceString
01/12/2013 10:55:35  9  INF                  Resource id to be retrieved is ExceptionInfo for language English (United States)
01/12/2013 10:55:35  9  INF                  Resource retrieved id ExceptionInfo is An exception of type {0} was thrown.  Additional exception information: {1}
01/12/2013 10:55:35  9  INF                Leaving function StringResourceManager.GetResourceString
01/12/2013 10:55:35  9  INF              Leaving function Common.BuildExceptionMessage
01/12/2013 10:55:35  9  INF            Leaving function Common.BuildExceptionInformation
01/12/2013 10:55:35  9  ERR            An exception of type Microsoft.SharePoint.Upgrade.SPUpgradeException was thrown.  Additional exception information: Action 4.0.14.0 of Microsoft.SharePoint.Upgrade.SPIisWebSiteWssSequence failed.
Microsoft.SharePoint.Upgrade.SPUpgradeException: Action 4.0.14.0 of Microsoft.SharePoint.Upgrade.SPIisWebSiteWssSequence failed. ---> System.Runtime.InteropServices.COMException (0x80071A91): Filename: \\?\C:\Windows\system32\inetsrv\config\applicationHost.config
Error: Cannot write configuration file
   at Microsoft.Web.Administration.Interop.AppHostWritableAdminManager.CommitChanges()
   at Microsoft.Web.Administration.Configuration.CommitChanges()
   at Microsoft.Web.Administration.ConfigurationManager.CommitChanges()
   at Microsoft.Web.Administration.ServerManager.CommitChanges()
   at Microsoft.SharePoint.Administration.SPIisServerManager.CommitChanges(ApplyChanges applyChanges)
   at Microsoft.SharePoint.Upgrade.EnableIIS7IntegratedMode.Upgrade()
   at Microsoft.SharePoint.Upgrade.SPActionSequence.Upgrade()
   --- End of inner exception stack trace ---

The Active directory LDAP object refered to does not exist in other SBS servers so I think that is a red herring.  I don't understand why the it can't write to the config file.  I've checked permissions and they all look normal and the same as other SBS servers.