I installed FUPPES, set a couple directories, and told it to start indexing. A short while later, it crashed with an access violation exception.
Not sure how much I can help with more information. I have a lot of MP3s with both tags and filenames in various encodings (ASCII, UTF-8, Shift-JIS,...), so it's possible that there is a problem there somewhere.
I'm running Windows XP x64 edition. I used the installation package to install FUPPES.
Let me know if I can provide more information.