php实现国际化问题

为什么我在生成hello.mo时，出错？错误信息如下：
D:\PHP_Project\Php_I18n>msgfmt -o hello.mo hello.po
(null): hello.po:21:11: invalid multibyte sequence
(null): hello.po:21:12: invalid multibyte sequence
(null): hello.po:21:13: invalid multibyte sequence
(null): hello.po:21:14: invalid multibyte sequence
(null): hello.po:21:17: invalid multibyte sequence
(null): hello.po:21:20: invalid multibyte sequence
(null): hello.po:21:25: invalid multibyte sequence
(null): hello.po:21:26: invalid multibyte sequence
(null): found 8 fatal errors                     
hello.po文件的内容：
PHP code:

# SOME DESCRIPTIVE TITLE.
# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
# This file is distributed under the same license as the PACKAGE package.
# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
#
#, fuzzy
msgid ""
msgstr ""
"Project-Id-Version: 0.1\n"
"Report-Msgid-Bugs-To: \n"
"POT-Creation-Date: 2009-11-30 16:30+0800\n"
"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
"Language-Team: LANGUAGE <LL@li.org>\n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=gb2312\