Hi @leila, I suspect you're on the right track here (looking at locale environment variables). You're probably looking for a locale that specifies .utf-8 or .UTF-8. The formatting (caps) depends on your system, and must be a perfect match.
I did a quick search for your error message, and there are a bunch of good topics troubleshooting this already. Start here, see if you can figure out what's going on, and let us know if it keeps giving you trouble!