I'm also having problems with this.
I have my IMAP email set up through cPanel and configured in outlook 2010.
I can send emails from the address but not receive them. My gmail I was testing with consistently received the same errors as TSF007 got.
edit: I was able to receive automated emails.. from myself. One from WordPress and one Outlook test message.
I still cannot receive emails from outside sources.
edit2: One from gmail just came in from a day ago, severely delayed, it may be because I just newly registed on heliohost and the cu.cc subdomain.