"Warning C0007: the architecture has unrelated instances."

I have the following source code from the CD that came with the book, "Basics of Digital Design."

When I tried to run the program, it gave me the following error:

Compiling Fig17_13.vhd...
C:\Users\SPIDER\Desktop\EE460\The Final Project\Fig17_13.vhd(25): Warning C0007 : Architecture has unbound instances (ex. ct2)
Done

How can I fix this problem?

Here is the code:

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

entity c74163test is
    port(ClrN,LdN,P,T1,Clk: in std_logic;
       Din1, Din2: in std_logic_vector(3 downto 0);
       Count: out integer range 0 to 255;
       Carry2: out std_logic);
end c74163test;

architecture tester of c74163test is
    component c74163
       port(LdN, ClrN, P, T, Clk : in std_logic;  
         D: in std_logic_vector(3 downto 0);
       Cout: out std_logic; Qout: out std_logic_vector(3 downto 0) );
    end component;
    signal Carry1: std_logic;
    signal Qout1, Qout2: std_logic_vector(3 downto 0);
begin
    ct1: c74163 port map (LdN,ClrN,P,T1,Clk,Din1,Carry1, Qout1);
    ct2: c74163 port map (LdN,ClrN,P,Carry1,Clk,Din2,Carry2,Qout2);
    Count <= Conv_integer(Qout2 & Qout1);
end tester;