System.NullReferenceException on step 8 of configuration wizard

Hi

When I run the configuration wizard I get a System.NullReferenceException on step 8.

Failed to install the application content files.
An exception of type System.NullReferenceException was thrown.  Additional exception information: Object reference not set to an instance of an object.
System.NullReferenceException: Object reference not set to an instance of an object.
   at Microsoft.SharePoint.Administration.SPAspConfigurationFile.ApplyActionToXmlDocument(XmlDocument xdAction, XmlDocument xd, String sourceFileName, SupportedXmlDocutmentActions supportedActions)
   at Microsoft.SharePoint.Administration.SPAspConfigurationFile.MergeWebConfig(XmlDocument xdWebConfig, String fileMask)
   at Microsoft.SharePoint.Administration.SPWebService.ApplyApplicationContentToLocalServer()
   at Microsoft.SharePoint.PostSetupConfiguration.ApplicationContentTask.Run()
   at Microsoft.SharePoint.PostSetupConfiguration.TaskThread.ExecuteTask()

Any ideas how to solve this ?

I need to apply the last PU and I need to have a good configuration before apply it because it gives the same error after apply it.

Thank you

Sorin Sandu