Ensure the class has a constructor

if there is no constructor (this means a model which does not inherit
from Model) newInstance will throw an exception.

lib/Cake/Utility/ClassRegistry.php

@@ -138,7 +138,11 @@ public static function init($class, $strict = false) {
 					if ($reflection->isAbstract() || $reflection->isInterface()) {
 						throw new CakeException(__d('cake_dev', 'Cannot create instance of %s, as it is abstract or is an interface', $class));
 					}
-					$instance = $reflection->newInstance($settings);
+					if ($reflection->getConstructor()) {
+						$instance = $reflection->newInstance($settings);
+					} else {
+						$instance = $reflection->newInstance();
+					}
 					if ($strict) {
 						$instance = ($instance instanceof Model) ? $instance : null;
 					}