You shouldn't rename anything or alter the files. As Sparen mentioned, you need to handle the zip with Japanese character support. If you don't know what any of this means, please google for unzipping in Japanese local or handling files with JP characters. It is bit difficult to explain it all here since partially it is OS dependant as well.
When you get errors during unzipping, it means you need to unzip it with Japanese Locale support (think 7zip does this?)
If you managed to unzip, run 0.12m with AppLocale > Japanese. In the FAQ/tutorials it is shown how to do this.