CCOmments just paid for upgrade to PRO. Had core installed. Ran the PRO download file. But getting errors. One is something about CURL. Then a 404 error.

Entering the Download ID is not sufficient for enabling CComment Professional's features. You will need to download and install the CComment Professional package on your site, without uninstalling the Core version.

CCOmments says its installed, but PRO features not working (i.e. can't use RECAPTCHA).

Help please