Corrupt japanese ZIP file?

I'm trying to open two different files, and the only thing in common they have is that they're both containing japanese characters.

If I open them using either WinZip or 7-Zip (the two unzipping programs installed on this PC), I get corrupted ASCII gibberish instead, and the files are wrecked too.

Can anyone tell me the fix for this? I'm using Windows Vista, most recent update, and Firefox 3.6 (I know, I know, but some of the addons I use weren't updated for newer FF versions).

If anyone cares/it changes anything, the files are japanese-only .ips and .ups patches for games.

 

I already know about .ips patching, thank you. And .ups is also a patch format that can be used with tsukuyomi and other UPS patchers, not just a Microsoft Works file.

My problem is that the zip files are corrupted because their contents contain japanese characters. The only references to the problem I found said it was an issue with non-unicode characters, and the only fix was for ubuntu.