If you have a bit older phone, using S60 2nd edition, such as Nokia N70, you have to download FExplorer 2nd edition, for Y-Browser supports no more phones of the 2nd edition.
You may then discover that the fonts are located at z:/system/fonts instead of z:/resource/fonts, so you have to install Japanese fonts at /system/fonts of your card memory
Don't forget to install also a Japanese gdr font by renaming to ceurope.gdr
