Did he save the source file with UTF-8 or UTF-16 encoding? It sounds like he
did not; instead it sounds like he used the default system code page (which
in his case is Japanese and in yours is not).

On US Windows XP SP2, I had to go into Control Panel - Regional Options and
set an option to extend support of advanced text services to all programs.
On US Windows 2003, this option is not available but isn't needed.  On
Japanese Windows systems this option isn't needed (whether or not it's
available).

On all Windows systems I have Japanese as the default language for
non-Unicode programs.  On Japanese Windows systems it's the default of
course, but on US Windows systems I had to set it.  This setting has no
serious side effects so I don't mind, though I do wonder why Visual Studio 6
and later, and Windows Explorer, seem to be non-Unicode programs (affected
by this option).

On all Windows systems I have Japanese as the option for Standards and
formats.  On Japanese Windows systems it's the default of course, but on US
Windows systems I had to set it.  This setting does have side effects,
causing other programs to display menus and help pages stuff in Japanese
even when I wanted them to stay in English.  I do not like the way some
operations of Visual Studio depend on this option instead of depending on
other more reasonable options for character encoding.

I don't remember how many of those options I needed for Visual Studio 6, how
many for 2003, and how many for 2005 beta 1.  You might not need all of
them.

In Visual Studio itself, there are options to select the fonts that will be
used for displaying its own windows, including displaying the contents of
source files.  You need fonts that include Japanese characters.