Missing required extension: XMLRPC

I'm trying to install KnowledgeTree Community Edition on my CentOS VPS. One of the requirements for this was ZendServer - Which I had to install via their universal installer as installing via YUM was just straight out failing. I assume due to CPanel...

Anyway, I got ZendServer installed and then downloaded the source of KnowledgeTree a开发者_运维问答nd dumped it in my webroot. When trying to run the web installer, however, I get:

Missing required extension: XMLRPC

ZendServer reports XMLRPC is turned on. I've downloaded, via YUM, xmlrpc and php-xmlrpc. I can't get this error to go away.

I don't think it's necessarily got anything to do with KnowledgeTree. According to Google, I'm the only person having this issue. So how can I get XMLRPC working on PHP? Despite the fact ZendServer already thinks it is working...

---

Freshly-installed PHP extension packages won't be recognized by the process running PHP (usually a web server) until it is restarted/bounced/whatnot.