Erhc only trades on one exchange in America called expert market OTC.
I think the question you're trying to ask is, are there brokers that are not American or Canadian which will allow you to purchase shares in ERHC?
Try SwissQuote Lux, I have heard that they do. But I'm not 100% sure. They definitely offer a bid ask quote on erhc, which few places do.
Americans can't open an account there, but if you have a second passport from anywhere else in the world other than American, then you can open an account.
Scotia iTrade and Questrade definitely allow purchases. But you need a non American passport. Calling them doesn't really help because the reps often don't realize that their systems will allow the trade even though it's caveat emptor stock. I don't like Questrade because they have weird quantity limits. Scotia is great.
There are several countries that offer second passports... Antigua, St. Lucia, etc.