How can I use LINQ in Crystal Report

Hi
I am using Crystal Report for creating a report. I have two tables, Driver_Specifications and Watch.
Primary key of Watch is foreign key of Driver_Specifications. I set some field in my report file to show the data of Driver_Specifications and I want to show a specific field of Watch instead of the foreign key of Driver_Specifications. What is the query of LINQ for this problem?
This is what I have so far:

var q = (from d in taxi_AgencyDataSet.Driver_Specifications 
         orderby d.First_Name, d.ID_Driver 
         select new 
         { 
             d.First_Name, 
             d.Last_Name, 
             d.Car_Name, 
             d.Car_Color, 
             d.WatchRow.Watch_Name, 
             d.ID_Watch 
         }).ToList(); 

I get the following error:

Object reference not set to an instance of an object