LINQ to SQL update woes.cs

using(var db = new FooDataContext())
{
    foreach(var row in table) 
    {
        Car car = (from c in db.Cars
                  where c.Id = row["CAR_ID"]).SingleOrDefault();

        if(car == null)
           car = new Car();
        
        car.Id = row["CAR_ID"];
        car.Name = row["CAR_NAME"];
 
        if(car.IsNew()) { 
            db.Cars.InsertOnSubmit(car);
        }  
    }

    db.SubmitChanges(); //error on the first update
}

//here is one of the SQL statements
UPDATE [dbo].[T_CARS]
SET [Name] = @p0, [update_id] = @p1, [update_ts] = @p2
WHERE 0 = 1  <----  WTH is this?

The error I get:
>>  System.Data.Linq.ChangeConflictException : Row not found or changed.