jbear6 -- Glad you got it working

If you feel that the installation instructions need revising or have any suggestions, please let me know.
andrewc_11890 - You need either CURL or the allow_url_fopen directive enabled. If you're using a hosted service, you'll need to contact your web host provider to enable one of these two options. If you run your own server, the easiest way to get it going is to edit your php.ini file and set allow_url_fopen to On. (allow_url_fopen = On) It's not necessary to have this option enabled for installation or use, but it does make installation a little faster and is required for using the Who's Chatting system.
kefallon - Not sure how that could have happened. I wouldn't recommend removing any files, but rather re-installing the files and making sure they've been copied to the correct location. In this case, it sounds (at the least) as though the addonchat.php file wasn't uploaded to the admincp/ folder.
acorndomains.co - Wonderful!

Glad everything is working well for you. Just an FYI, we do have a UK division (support@addonchat.co.uk) should you need assistance they may be able to answer enquiries a little faster for you if you're across the pond.
CNibbana - Great to hear! eMail
support@addonchat.com with your account number and the service level you think you may be interested in getting, and we'll be happy to give you a two week trial.