I have another theory as to why Limewire 4.9.x does not return many Kanji results. this is becuase it has been redesigned to connect to Gnutella servers close to your physical (or connection) location. If you are not connecting to an ISP in the far east, the Gnutella hosts in your location may not have many Kanji named files to begin with and you'll receive few menaingful results.

It might be worth a try to proxy Limewire 4.9.x though a far eastern server and then Limewire would connect to the Gnutella hosts local to the proxying machine rather than your ISP's location.