这个这个堆栈跟踪信息是什么个意思？怎么解决

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.CMS.BackgroundPages.ConsoleTableMetadata.Page_Load(Object sender, EventArgs E) +1030
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) +91
System.Web.UI.Control.LoadRecursive() +74
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2207

空引用。打个断点一步一步跟吧

该字符串未被识别为有效的 datetime。 说明: 执行当前 web 请求期间，出现未处理的异常。请检查堆栈跟踪信息，以了解有关该错误以及代码中导致错误的出处的详细信息。 异常详细信息: system.formatexception: 该字符串未被识别为有效的 datetime。 源错误: 执行当前 web 请求期间生成了未处理的异常。可以使用下面的异常堆栈跟踪信息确定有关异常原因和发生位置的信息。 堆栈跟踪: [formatexception: 该字符串未被识别为有效的 datetime。] system.datetimeparse.parse(string s, datetimeformatinfo dtfi, datetimestyles styles) +4588098 system.convert.todatetime(string value) +66 lonmeshop.web.ui.cart.addshoppingcart() +738 controls_goods.addshopingcart_click(object sender, imageclickeventargs e) +1284 system.web.ui.webcontrols.imagebutton.onclick(imageclickeventargs e) +98 system.web.ui.webcontrols.imagebutton.raisepostbackevent(string eventargument) +161 system.web.ui.page.raisepostbackevent(ipostbackeventhandler sourcecontrol, string eventargument) +29 system.web.ui.page.processrequestmain(boolean includestagesbeforeasyncpoint, boolean includestagesafterasyncpoint) +2981