Compiler error help

hey guys,

I'm trying to compile some code but i keep getting the following error:

Error (10028): Can't resolve multiple constant drivers for net "ctr[3]" at MainTimer2.vhd(43)

here is the file that is causing the problem:

library ieee;

use ieee.std_logic_1164.all;

use ieee.std_logic_unsigned.all;

use ieee.numeric_std.all;

use IEEE.numeric_std;

entity MainTimer2 is

port(

CLK : in std_logic;

CLK_en: in std_logic;

count_en: in std_logic;

syst_reset: in std_logic;

maxNUM: in std_logic_vector(3 downto 0);

ctr: inout std_logic_vector(3 downto 0);

finished: inout std_logic);

end entity MainTimer2;

architecture behavioral of MainTimer2 is

signal en : std_logic;

begin

process(CLK) begin

if (syst_reset = '1') then

ctr<=maxNum;

finished<='1';

end if;

if(RISING_EDGE(CLK) and count_en='1') then

if(finished='1') then

en<='0';

else

en<='1';

end if;

end if;

end process;

process (CLK_en) begin

if(RISING_EDGE(CLK_en) and en='1' ) then

if (ctr = "0000") then

ctr<="0000";

finished<='1';

else

ctr<=ctr-1;

finished<='0';

end if;

end if;

end process;

end behavioral ;

the error is being generated from the second process statement but i dont understand why. any help would be greatly appreciated.