Hello Umbracians,

I've got a development site up on Vidahost and it was working fine over the weekend, no one has accessed the backend of Umbraco so not sure what has gone but i now get this error.

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.]
   umbraco.library.GetXmlNodeByXPath(String xpathQuery) +83

[TargetInvocationException: Exception has been thrown by the target of an invocation.]
   System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) +0
   System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments) +76
   System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) +193
   UmbracoExamine.DataServices.UmbracoContentService.GetPublishedContentByXPath(String xpath) +117
   UmbracoExamine.BaseUmbracoIndexer.AddNodesToIndex(String xPath, String type) +31
   UmbracoExamine.BaseUmbracoIndexer.PerformIndexAll(String type) +1008
   UmbracoExamine.UmbracoContentIndexer.PerformIndexAll(String type) +618
   UmbracoExamine.BaseUmbracoIndexer.PerformIndexRebuild() +98
   Examine.ExamineManager._RebuildIndex() +141
   Umbraco.Web.WebBootManager.<InitializeResolvers>b__c() +277
   Umbraco.Core.Sync.DatabaseServerMessenger.Initialize() +370
   Umbraco.Core.Sync.DatabaseServerMessenger.Boot() +194
   Umbraco.Core.CoreBootManager.<Complete>b__8(IApplicationEventHandler x) +220
   Umbraco.Core.EnumerableExtensions.ForEach(IEnumerable`1 items, Action`1 action) +148
   Umbraco.Core.CoreBootManager.Complete(Action`1 afterComplete) +320
   Umbraco.Web.WebBootManager.Complete(Action`1 afterComplete) +95
   Umbraco.Core.UmbracoApplicationBase.StartApplication(Object sender, EventArgs e) +355

[HttpException (0x80004005): Exception has been thrown by the target of an invocation.]
   System.Web.HttpApplicationFactory.EnsureAppStartCalledForIntegratedMode(HttpContext context, HttpApplication app) +12964021
   System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr appContext, HttpContext context, MethodInfo[] handlers) +175
   System.Web.HttpApplication.InitSpecial(HttpApplicationState state, MethodInfo[] handlers, IntPtr appContext, HttpContext context) +304
   System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context) +404
   System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext) +475

[HttpException (0x80004005): Exception has been thrown by the target of an invocation.]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +12981028
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +159
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +12820621

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.34274

I believe this may be something to do with one of the surface controllers i have for the custom built contact form.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Xml.XPath;
using Umbraco.Core.Services;
using Umbraco.Web.Mvc;

/// <summary>
/// Summary description for ContactSurfaceController
/// </summary>

namespace LiquidThinker2015
{
    public class ContactSurfaceController : SurfaceController
    {
        public object XPathModeIterator { get; private set; }

        public ActionResult ShowForm()
        {
            ContactModel myModel = new ContactModel();
            List<SelectListItem> ListOfServices = new List<SelectListItem>();
            XPathNodeIterator iterator = umbraco.library.GetPreValues(1435);
            iterator.MoveNext();
            XPathNodeIterator preValues = iterator.Current.SelectChildren("preValue", "");
            while (preValues.MoveNext())
            {
                string preValue = preValues.Current.GetAttribute("id", "");
                ListOfServices.Add(new SelectListItem
                {
                    Text = preValues.Current.Value,
                    Value = preValues.Current.GetAttribute("id","")
                });
                myModel.ListOfServices = ListOfServices;
            }
            return PartialView("ContactForm", myModel);
        }

        public ActionResult HandleFormPost(ContactModel model)
        {
            var newComment = Services.ContentService.CreateContent(model.Name + " - " + DateTime.Now.ToString("dd/MM/yyyy HH:mm"), CurrentPage.Id, "ContactFormula");

            //DataTypeService myService = new DataTypeService();
            //var SelectedService = myService.GetAllDataTypeDefinitions().First(x => x.Id == 1435);
            //int SelectedServicePreValueId = myService.GetPreValuesCollectionByDataTypeId(SelectedService.Id).PreValuesAsDictionary.Where(x => x.Value.Value == model.SelectedService).Select(x => x.Value.Id).First();


            newComment.SetValue("contactName", model.Name);
            newComment.SetValue("companyName", model.Company);
            newComment.SetValue("emailFrom", model.Email);
            newComment.SetValue("telephoneNumber", model.Telephone);
            newComment.SetValue("dropdownServices", model.SelectedService);
            newComment.SetValue("contactMessage", model.Message);

            Services.ContentService.SaveAndPublishWithStatus(newComment);

            return RedirectToUmbracoPage(1454);
            //return RedirectToCurrentUmbracoPage();
        }
    }
}

Any ideas as to what's gone wrong here? I guess there is a value not being set somewhere?