Use MP3Gain and MP3val with unicode filenames

MP3Gain and MP3val are two essential tools if you want to maintain a good mp3 collection. Mp3gain makes your songs all the same volume, and Mp3val scans mp3 files for errors and fixes them. Unfortunately, both tools don't work with certain unicode filenames, such as Russian (Cyrillic), Chinese, Japanese and so on. They won't recognize files with special characters in their name. But thankfully, there's a workaround.
If you're using Windows Vista, 7 or 8, you can change the system locale. See how it's done!
Follow these instructions and set your system locale to Russian (Cyrillic), for example. After that, MP3Gain and Mp3val will be able to recognize cyrillic characters in your filenames.
If you're using Windows XP, see here for changing the system locale:
http://smart-planet.blogspot.de/2011/01/change-system-locale-for-windows-xp.html
http://www.eclipsecrossword.com/help-system-locale-xp.html
Another workaround is a Microsoft tool called AppLocale which deals with this issue. Just start it, select your application, then select the appropriate language and run. Both tools will now recognize the unicode filenames. However, it didn't quite work for me. The filenames were displayed correctly in the tools, but the files couldn't be read and written correctly. Setting the system locale works much better (see above).
Note: If you're using Vista or Windows 7 / 8, AppLocale will refuse to install. This is because it needs administrator privileges to run. You cannot right-click and run as administrator because the installer is an MSI package and not an exe file. The trick is to open an elevated command prompt with administrator privileges and run the MSI package from there. AppLocale will now install fine.