PHP - SSL certificate error unable to get local issuer certificate

Question

PHP 5.6.3 is being used by XAMPP on Windows 7 for me. I'm encountering the following problem while attempting to utilize the Mandrill API:

Uncaught exception 'Mandrill_HttpError' with message 'API call to messages/send-template failed: SSL certificate problem: unable to get local issuer certificate'

The following was added to the php.ini file, and I have already tried everything I read on StackOverflow:

curl.cainfo = "C:\xampp\php\cacert.pem"

And naturally downloaded the cacert.pem file from http://curl.haxx.se/docs/caextract.html to that directory.

XAMPP and Apache server were restarted after all of that, however, the issue remained. I'm not sure what else to attempt. Who can give me advice on what I should do next?