Help with Entity Framework, asp.net

I am trying to duplicate the example discussed at: https://www.youtube.com/watch?v=Z7713GBhi4k  You-Tube example displays Location names (a one-side field) along with Employee data (many-side). Because I am using a different database, my sample uses:

 Customers names (a one-side field) along with Order data (many-side).

Question: How can I display Customer orders in nested gridview controls similar to the sample shown below?

I have the entire solution in zip file (Entity_Utube.zip about 2.7MB with the database in it). But because this files contains files with .sln extention, EE doesn't allow to be uploaded. Gmail account does the same but hotmail accounts allow this attachement. I will be glad to email it to you if you eamil me at eghtebas<at>hotmail<dot>com using a non-gmail account with subject line EE Question. This might help to quickly spot the following error messages:

Server Error in '/' Application.

The result type of the query is neither an EntityType nor a CollectionType with an entity element type. An Include path can only be specified for a query with one of these result types.

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.InvalidOperationException: The result type of the query is neither an EntityType nor a CollectionType with an entity element type. An Include path can only be specified for a query with one of these result types.

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: 


[InvalidOperationException: The result type of the query is neither an EntityType nor a CollectionType with an entity element type. An Include path can only be specified for a query with one of these result types.]
   System.Data.Objects.Internal.ObjectFullSpanRewriter..ctor(DbCommandTree tree, DbExpression toRewrite, Span span, AliasGenerator aliasGenerator) +8589308
   System.Data.Objects.Internal.ObjectSpanRewriter.TryRewrite(DbQueryCommandTree tree, Span span, MergeOption mergeOption, AliasGenerator aliasGenerator, DbExpression& newQuery, SpanIndex& spanInfo) +80
   System.Data.Objects.Internal.ObjectQueryExecutionPlan.Prepare(ObjectContext context, DbQueryCommandTree tree, Type elementType, MergeOption mergeOption, Span span, ReadOnlyCollection`1 compiledQueryParameters, AliasGenerator aliasGenerator) +66
   System.Data.Objects.EntitySqlQueryState.GetExecutionPlan(Nullable`1 forMergeOption) +414
   System.Data.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption) +131
   System.Data.Objects.ObjectQuery`1.GetIListSourceListInternal() +13
   System.Data.Objects.ObjectQuery.System.ComponentModel.IListSource.GetList() +10
   System.Web.UI.WebControls.EntityDataSourceView.ContinueSelectTyped(DataSourceSelectArguments arguments, EntityDataSourceQueryBuilder`1 queryBuilder, ObjectQuery`1 queryT, Boolean wasQueryModified) +295
   System.Web.UI.WebControls.EntityDataSourceView.ExecuteSelectTyped(DataSourceSelectArguments arguments, Creator qbConstructor) +2189
   System.Web.UI.WebControls.EntityDataSourceView.ExecuteSelect(DataSourceSelectArguments arguments) +513
   System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback) +21
   System.Web.UI.WebControls.DataBoundControl.PerformSelect() +138
   System.Web.UI.WebControls.BaseDataBoundControl.DataBind() +30
   System.Web.UI.WebControls.GridView.DataBind() +4
   System.Web.UI.WebControls.BaseDataBoundControl.EnsureDataBound() +105
   System.Web.UI.WebControls.CompositeDataBoundControl.CreateChildControls() +75
   System.Web.UI.Control.EnsureChildControls() +83
   System.Web.UI.Control.PreRenderRecursiveInternal() +42
   System.Web.UI.Control.PreRenderRecursiveInternal() +155
   System.Web.UI.Control.PreRenderRecursiveInternal() +155
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +974

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.34237

Select allOpen in new window

Also, here is the image from You-Tube example: