Getting a little frustrated now so thought it easier to ask the question!
I have enabled the "Use MailChimp AutoResponder" checkbox and added my list name and API but when a new user signs up nothing happens i.e. they don't get added to my Mailchimp newsletter.
I have also enabled "Enable Debug" and had a look inside all of the .log files in the ipn folder of emember but nothing!
Please help.