NullReferenceException while get Data from Memcached (.NET)

Have problem while getting data from Memcached on .NET MVC solution.

I have this custom repository:

public List<DropDownLocalization> GetLocalization(string key, string lang)
        {
            var result = cacheClient.Get<IQueryable<DropDownLocalization>>("DD_" + key + "_" + lang);
            if (result == null)
            {
                int getLangId = _db.languages.Where(d => d.Association == lang).Select(d => d.Id).FirstOrDefault();
                int getLableItemId = _db.lables_dropdown.Where(d => d.Key == key).Select(d => d.Id).FirstOrDefault();
                var get = _db.lables_dropdown_items.Where(d => d.LableId == getLableItemId).Select(d => new DropDownLocalization
                                                    {
                                                        DDId = d.Id,
                                                        DDName = d.lables_dropdown_values.Where(m => m.Language == getLangId).Select(m => m.Value).FirstOrDefault()
                                                    }).AsQueryable();
                cacheClient.Store(StoreMode.Add, "DD_" + key + "_" + lang, (IQueryable<DropDownLocalization>)get);
                EFQueryLogger.WriteQuery(((ObjectQuery)get).ToTraceString());
                return get.ToList();
            }
            return result.ToList();
        }

It's get list of drop down labels localized from current lang.

So it's trying to get data from cache, if not success put data to cache. While i comment part of code with "if" statement (just to see if it's get data data from cache) i have error of null reference. It's mean that request response is not in the cache.

Can somebody put my nose to the problem?

There is my enym client library config:

<enyim.com>
    <memcached protocol="Text">
      <servers>
                <add address="localhost" port="11211" />
      </servers>
      <socketPool deadTimeout="00:00:10" />
    </memcached>
  </enyim.com>

Solution found. Unfortunately it was my mistakes. There is the practice how to store data model in memcached.

I have model:

[Serializable]
    public class DropDownLocalization
    {
        public int DDId { get; set; }
        public string DDName { get; set; }
    }

And method that return result:

public List<DropDownLocalization> GetLocalization(string key, string lang)
        {
           List<DropDownLocalization> result = MemcachedSingleton.Instance.Get<List<DropDownLocalization>>("DD_" + key + "_" + lang);
           if (result == null)
           {
               int getLangId = _db.languages.Where(d => d.Association == lang).Select(d => d.Id).FirstOrDefault();
               int getLableItemId = _db.lables_dropdown.Where(d => d.Key == key).Select(d => d.Id).FirstOrDefault();
               result = _db.lables_dropdown_items.Where(d => d.LableId == getLableItemId).Select(d => new DropDownLocalization
                                                   {
                                                       DDId = d.Id,
                                                       DDName = d.lables_dropdown_values.Where(m => m.Language == getLangId).Select(m => m.Value).FirstOrDefault()
                                                   }).ToList();
               MemcachedSingleton.Instance.Store(StoreMode.Add, "DD_" + key + "_" + lang, result);
               return result;
           }
           return result;
        }

It's fully working now.

Config should be next:

<enyim.com>
    <memcached protocol="Text">
      <servers>
        <add address="localhost" port="11211" />
      </servers>
      <transcoder type="Enyim.Caching.Memcached.DataContractTranscoder, Enyim.Caching" />
      <socketPool deadTimeout="00:00:10" />
    </memcached>
  </enyim.com>