kernel debugger cannot start on win 2000

[wong_powah@yahoo.ca]

In the testing system, i change the boot.ini file to
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(2)\WINNT
[operating systems]
multi(0)disk(0)rdisk(0)partition(2)\WINNT="Microsoft Windows 2000
Professional"
/fastdetect
multi(0)disk(0)rdisk(0)partition(2)\WINNT="Microsoft Windows 2000
Professional debug" /debug /debugport=com1 /baudrate=115200

After that, i restarted my Testing system and choose option "debug".

cd C:\"Program Files\Debugging Tools for Windows"
set _nt_debug_port=com1
set _nt_symbol_path=c:\debug\symbols
set _nt_debug_log_file_append=c:\temp\debug.log


C:\Program Files\Debugging Tools for Windows>.\kd

Microsoft (R) Windows Debugger Version 6.6.0007.5
Copyright (c) Microsoft Corporation. All rights reserved.

Failed to open \\.\com1
Kernel debugger failed initialization, Win32 error 2
"The system cannot find the file specified."
Debuggee initialization failed, Win32 error 2
"The system cannot find the file specified."

My OS is Windows 2000 SP4.
I connect my computer with another computer on com1 with a null modem
cable.