Thread:Extension talk:CirrusSearch/Fatal Error: Class Not Found (new installation)

I'm encountering an error with CirrusSearch both from CLI and MW1.24.

CLI ouput:

$> php updateSearchIndexConfig.php PHP Fatal error: Class 'CirrusSearch\Connection' not found in /opt/www/sites/mediawiki/extensions/CirrusSearch/maintenance/updateSearchIndexConfig.php on line 47

Output of error.log:

2015/04/08 13:27:16 [error] 2266#0: *146 FastCGI sent in stderr: "PHP message: PHP Fatal error: Cannot instantiate abstract class ElasticaConnection in /opt/www/sites/mediawiki/extensions/Elastica/ElasticaConnection.php on line 37" while reading response header from upstream, client: [ipaddress], server: [servername], request: "GET /index.php?search=audit&title=Special%3ASearch&go=Go HTTP/1.1", upstream: "fastcgi://unix:/var/run/php-fpm.sock:", host: "[servername]", referrer: "[servername]/Main_Page"

LocalSettings.php

require_once "$IP/extensions/Elastica/Elastica.php";

require_once "$IP/extensions/CirrusSearch/CirrusSearch.php";

$wgDisableSearchUpdate = true;

$wgCirrusSearchServers = array( 'localhost' );

$wgSearchType = 'CirrusSearch';

File permissions appear to be properly set. All other extensions are functioning (including Elastica).

Can anyone provide some insight into how this may be resolved?