There is some information in the release notes:
which may be relevant. Note 6.8 in particular may apply. I'm not sure, but it may be worth a read.
Unfortunately, uncomment this line of code does not help
$__FM_CONFIG['curlOptions'] = array(CURLOPT_SSL_VERIFYPEER => false);
I am running into the same problem. Slightly different configuration: OS X 10.8.5, FMS 12.04.
I tried the recommendation to uncomment the line of code in the configuration file, but it also did not appear to work for my problem. I edited the file in the 'Mountain Lion' subdir, though, in the path that was noted in the advanced release notes, and not Lion. I restarted the WPC component of FMS using the Admin console as well. (Didn't specify that in the release notes, but just in case...)
This error manifests itself only when I redirect all HTTP traffic to the HTTPS website. I am using Server.app on OS X to make these changes.
Any other suggestions would be helpful.