I have Japanese W2K and I couldn't even start installation. The problem was Locale and Language setting. This is how I could successfully installed SW onto my Japanese W2K.
1. Go to Control Panel and open Regional Option.
2. Change Locale to English. and change default language setting to English.
(I believe you have to reboot.)
3. Read FAQ here and try "clean install". Make sure if everything is OK.
4. Go back to Control Panel and change the default language to whatever you want. I would recommend to keep English as "Locale" if you live in US because some of anti-virus program refers it when you update definition file.
SW (installation program) doesn't like other languages than English and I sent a complain to SW that the installation program should accept other languages than English as well, but so far no luck.. You can switch back to your language after installation is done and works fine.