I'm working on integrating a previously built Sitecore solution (web project as well as TDS items) into the current Sitecore solution we are building. I've been working through a variety of Application errors that have sprung up during this migration, but I seem to be stuck on this one related to Glassmapper. The application is throwing a NullReferenceException at the following line:

```
string.IsNullOrEmpty(Model.BackgroundImage) ? "bg-primary-dark" : string.Empty)" style="background-image: url('@Model.BackgroundImage.Src')

```

When I step through using the debugger, I can see that Model.BackgroundImage is null. However, the ID in the Model is set to the appropriate Sitecore item. So it seems as though Glassmapper is finding the item, but not resolving the fields correctly. 

This is the Model itself. It was working without error before I began trying to integrate the old Sitecore solution:

```
using Glass.Mapper.Sc.Configuration.Attributes;

namespace Site.Models
{
    [SitecoreType(AutoMap=true, TemplateId= "{5DADD454-BB7D-46A4-AF64-0C169DBDAF79}")]
    public class HomePageHero : GlassBase, IHomePageHero
    {
        public new static string ModelTemplateId { get { return "{5DADD454-BB7D-46A4-AF64-0C169DBDAF79}"; } }

        public virtual string FirstTextLine { get; set; }

        public virtual string SecondTextLine { get; set; }

        public virtual string ThirdTextLine { get; set; }

        public virtual Glass.Mapper.Sc.Fields.Image BackgroundImage { get; set; }

        public virtual Glass.Mapper.Sc.Fields.Link ButtonLink { get; set; }
    }
}

```

And this is how I'm inheriting the Model in the .cshtml file:

```
@inherits Glass.Mapper.Sc.Web.Mvc.GlassView<HomePageHero>

```

Does anyone have an idea of what might be going on here?