Un-handled error in Global.asax Application ONERROR.

Object reference not set to an instance of an object.
System.NullReferenceException: Object reference not set to an instance of an object.
   at w3a.Inigo.Global.Application_Error(Object sender, EventArgs e)

Original error was.
The file '/templates/juddmonte.aspx' does not exist.
System.Web.HttpException (0x80004005): The file '/templates/juddmonte.aspx' does not exist.
   at System.Web.UI.Util.CheckVirtualFileExists(VirtualPath virtualPath)
   at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
   at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
   at System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory(VirtualPath virtualPath, HttpContext context, Boolean allowCrossApp, Boolean throwIfNotFound)
   at System.Web.Compilation.BuildManager.CreateInstanceFromVirtualPath(VirtualPath virtualPath, Type requiredBaseType, HttpContext context, Boolean allowCrossApp)
   at System.Web.UI.PageHandlerFactory.GetHandlerHelper(HttpContext context, String requestType, VirtualPath virtualPath, String physicalPath)
   at System.Web.UI.PageHandlerFactory.System.Web.IHttpHandlerFactory2.GetHandler(HttpContext context, String requestType, VirtualPath virtualPath, String physicalPath)
   at System.Web.HttpApplication.MapHttpHandler(HttpContext context, String requestType, VirtualPath path, String pathTranslated, Boolean useAppConfig)
   at System.Web.HttpApplication.MapHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)