I have my unite account setup and I added myself as a user. When it asked for my email address I gave it my blackberry.net email but it keeps saying it cant register it for some reason. Which email address do i need to use?

You don't need to add any email addresses, but those you do add need to support POP3 or IMAP access. I'm guessing that the blackerry.net addresses don't. A Gmail address will work.