I was having a issue with a wordpress plugin for a customer and was getting a “unable to get local issuer certificate” error
After a bit is research i found that the curl.cainfo= was missing from the php.ini file.
I downloaded the cacert.pem from http://curl.haxx.se/docs/caextract.html (Right Click save as)
Copied it to C:\Program Files (x86)\PHP
and added curl.cainfo=”C:\Program Files (x86)\PHP\cacert.pem” to the php.ini files. (for both 5.3 and 5.4)
Did a iisreset and all good. =)