LINQ Cross Join Error

I got this error

Object of type 'System.Data.Objects.ObjectQuery`1[XXX.Model.Cust_ProfileTbl]' cannot be converted to type 'System.Data.Entity.DbSet`1XXX.Core.Model.Cust_ProfileTbl]

When I tried CROSS JOINing these 2 tables with LINQ. Could anyone advise what should I do?

var Cust_ProfileTbl = service.DBContext.Set<Cust_ProfileTbl>();
var Cust_GroupTbl = service.DBContext.Set<Cust_GroupTbl>();

var test =
from cg in Cust_GroupTbl
from c in Cust_ProfileTbl
select new { intCustGroup = cg.intCustGroup, bintAccountNo = c.bintAccountNo };

Cust_ProfileTbl.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
namespace XXXX.Core.Model
{
    [Table("Cust_ProfileTbl")]
    public partial class Cust_ProfileTbl  
    {
        [Key]
        public long bintAccountNo { get; set; }
    }
}

Cust_GroupTbl.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
namespace xxxx.Core.Model
{
    [Table("Cust_GroupTbl")]
    public partial class Cust_GroupTbl
    {
        [Key]
        public int intCustGroup { get; set; } 
    }
}

Thanks in advance.

tan