siteserver cms 错误 帮忙分析下

[blank223]

在siteserver bin目录中上传了几个dll出现错误，删除后错误如下请问如何解决？

Server Error in '/' Application.
Object reference not set to an instance of an object.
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.NullReferenceException: Object reference not set to an instance of an object.

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:

[NullReferenceException: Object reference not set to an instance of an object.]
   SiteServer.Core.PageUtility.DetermineRedirectToInstaller() +52
   SiteServer.BackgroundPages.GeneralInitialization.Page_Load(Object sender, EventArgs e) +135
   System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14
   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35
   System.Web.UI.Control.OnLoad(EventArgs e) +99
   System.Web.UI.Control.LoadRecursive() +50
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627

[IHandler]

未将对象引用设置到对象的实例
也就是说对象不存在的时候被强行调用

调用前判断一下