This means that your game has files with non-ASCII filenames, and that the tool that you are using to zip them up is using an encoding other than UTF-8. There are three ways to fix this:
- Don't use non-ASCII filenames. Stick to the basics: a-z, 0-9, "-", "_", and ".", no accents or other diacritics.
- Find a better tool to zip up the files that uses UTF-8. Unfortunately I can't recommend any specific tool.
- Use butler to upload your project, which will presumably handle the UTF-8 encoding for you.