Let's see if we can figure this out. You received an e-mail that says you were invited and contains a login link. When you follow that link, you should be seeing a page that enables you to create a password. What are you seeing? A blank page? Is there any text or error at all?
The best way to solve this would be to forward your message to Tami at info@. She can try it herself, or ask me if it won't work for her either.