Enumeration yielded no result?

I am trying to filter some objects using linq to enitites and I get an error telling me "Enumeration yielded no results".

on the client side I get a message like this:

The operation cannot be completed because the DbContext has been disposed

I know that these filter values should return some results but it just doesnt work, so Im guessing my query is wrong, can you help please.

var mediaChannels =
NeptuneUnitOfWork.MediaChannels
          .FindWhere(m => m.CountryID == CountryID && 
                          m.SonarMediaTypeID == MediaTypeID &&
                          m.SonarMediaTypes.SonarMediaGroupID == MediaGroupID &&
                          m.Name.Contains(search))
          .Select(m => new MediaChannelModel() {
                 ID = m.ID,
                 Name = m.Name,
                 MediaType = m.MediaType.Name,
                 Country = m.Countries.Name,
                 SubRegion = m.Countries.Lookup_SubRegions.Name,
                 Region = m.Countries.Lookup_SubRegions.Lookup_Regions.Name
      });