Enterprise library 6 Enterprise Library 6.0参数不能为空

我在global.asax文件中设置了下面提到的exceptionmanager

protected void Application_Start(object sender, EventArgs e)
        {
            IConfigurationSource source = ConfigurationSourceFactory.Create();
            DatabaseFactory.SetDatabaseProviderFactory(new DatabaseProviderFactory(source));

            var logwriterFactory = new LogWriterFactory(source);
            var logWriter = logwriterFactory.Create();
            Logger.SetLogWriter(logWriter);

            var exceptionPolicyFactory = new ExceptionPolicyFactory(source);
            var exceptionManager = exceptionPolicyFactory.CreateManager();
            ExceptionPolicy.SetExceptionManager(exceptionManager);

但在使用enterprise library 6.0异常处理时，我仍然面临这个问题

请帮我解决这个问题