diff --git a/application/libraries/Zend/Form/Element/Captcha.php b/application/libraries/Zend/Form/Element/Captcha.php
index d18ba8403..179ca957b 100644
--- a/application/libraries/Zend/Form/Element/Captcha.php
+++ b/application/libraries/Zend/Form/Element/Captcha.php
@@ -228,7 +228,7 @@ public function getPluginLoader($type)
      */
     public function addPrefixPath($prefix, $path, $type = null)
     {
-        $type = strtoupper($type);
+        $type = is_string($type) ? strtoupper($type) : $type;
         switch ($type) {
             case null:
                 $loader = $this->getPluginLoader(self::CAPTCHA);