Koken depends on the positional output of get_declared_classes(), which can not be guaranteed. This extract the class name from the plugin instead.

[koken] extract_classname.diff

diff --git a/app/application/libraries/shutter.php b/app/application/libraries/shutter.php
index 6308d6c..58f7127 100755
--- a/app/application/libraries/shutter.php
+++ b/app/application/libraries/shutter.php
@@ -68,6 +68,18 @@ class Shutter {
 		return $json;
 	}
 
+	// tokenize a given file, and extract the class name
+	public static function extract_classname($file) {
+		$contents = file_get_contents($file);
+		$tokens = token_get_all($contents);
+
+		foreach($tokens as $i => $token) {
+		  if ($token[0] === T_CLASS) {
+		    return $tokens[$i+2][1];
+		  }
+		}
+	}
+
 	public static function init()
 	{
 		$root = dirname(dirname(dirname(dirname(__FILE__))));
@@ -84,8 +96,7 @@ class Shutter {
 			if ($fileinfo->isDir() && !$fileinfo->isDot() && file_exists($plugin)) {
 				include($plugin);
 				$data = json_decode(file_get_contents($info), true);
-				$klasses = get_declared_classes();
-				$last = array_pop( $klasses );
+				$last = self::extract_classname($plugin);
 				$data['php_class'] = new $last;
 				$data['php_class_name'] = get_class($data['php_class']);
 				self::$active_plugins[] = $data['php_class_name'];
@@ -129,8 +140,7 @@ class Shutter {
 							if ($matches && !class_exists($matches[1]))
 							{
 								include($plugin);
-								$klasses = get_declared_classes();
-								$last = array_pop( $klasses );
+								$last = self::extract_classname($plugin);
 								$data['php_class'] = new $last;
 								$data['php_class_name'] = get_class($data['php_class']);
 								self::$class_map[ $data['php_class_name'] ] = $data['php_class'];
@@ -578,4 +588,5 @@ class KokenPlugin {
 	}
 }
 
-Shutter::init();
\ No newline at end of file
+Shutter::init();
+

This problem arises if using HHVM instead of PHP5. Confirmed here: https://github.com/facebook/hhvm/blob/master/hphp/doc/inconsistencies#L122-L124