NDE.net Page Error

Type: "System.NullReferenceException"

ErrorMessage: "System.NullReferenceException: Object reference not set to an instance of an object.
   at report.Page_Init(Object sender, EventArgs e) in c:\projects\NDE2013\NDE3\report.aspx.cs:line 904
   at System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e)
   at System.EventHandler.Invoke(Object sender, EventArgs e)
   at System.Web.UI.Control.OnInit(EventArgs e)
   at System.Web.UI.Page.OnInit(EventArgs e)
   at System.Web.UI.Control.InitRecursive(Control namingContainer)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)"
Module name: NDE3.dll
Target name: Page_Init
Method: System.RuntimeMethodHandle