我修改Web.config的节点属性由安装时的 Off 改为RemoteOnly，又改回Off 以后，提示如下：
Server Error in '/' Application.
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Root element is missing.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Xml.XmlException: Root element is missing.
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace:
[XmlException: Root element is missing.]
System.Xml.XmlTextReaderImpl.Throw(Exception e) +90
System.Xml.XmlTextReaderImpl.ThrowWithoutLineInfo(String res) +109
System.Xml.XmlTextReaderImpl.ParseDocumentContent() +1954433
System.Xml.XmlTextReaderImpl.Read() +41
System.Xml.XmlLoader.Load(XmlDocument doc, XmlReader reader, Boolean preserveWhitespace) +145
System.Xml.XmlDocument.Load(XmlReader reader) +96
System.Xml.XmlDocument.Load(String filename) +160
Discuz.Config.GeneralConfigFileManager.ReviseConfig() +81
Discuz.Config.GeneralConfigFileManager..cctor() +152
[TypeInitializationException: The type initializer for 'Discuz.Config.GeneralConfigFileManager' threw an exception.]
Discuz.Config.GeneralConfigFileManager.LoadConfig() +0
Discuz.Config.GeneralConfigs..cctor() +74
[TypeInitializationException: The type initializer for 'Discuz.Config.GeneralConfigs' threw an exception.]
Discuz.Forum.HttpModule.ReUrl_BeginRequest(Object sender, EventArgs e) +90
System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +92
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +64
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Version Information: Microsoft .NET Framework Version:2.0.50727.1434; ASP.NET Version:2.0.50727.1434
