diff --git a/includes/derivatives.inc b/includes/derivatives.inc
index c66944b1..8a6627e5 100644
--- a/includes/derivatives.inc
+++ b/includes/derivatives.inc
@@ -60,9 +60,14 @@ function islandora_do_derivatives(AbstractObject $object, array $options) {
       require_once $hook['file'];
     }
     foreach ($hook['function'] as $function) {
-      $logging = call_user_func($function, $object, $options['force']);
-      if (!empty($logging)) {
-        $results[] = $logging;
+      if (function_exists($function)) {
+        $logging = call_user_func($function, $object, $options['force']);
+        if (!empty($logging)) {
+          $results[] = $logging;
+        }
+      }
+      else {
+        watchdog('islandora', 'Unable to call derivative function @function as it was not found!', array('@function' => $function), WATCHDOG_ERROR);
       }
     }
   }
diff --git a/includes/tuque_wrapper.inc b/includes/tuque_wrapper.inc
index 96f9919c..2aa85a8b 100644
--- a/includes/tuque_wrapper.inc
+++ b/includes/tuque_wrapper.inc
@@ -207,6 +207,7 @@ class IslandoraFedoraApiM extends FedoraApiM {
       'params' => $params,
     );
     islandora_alter_datastream($object, $datastream, $context);
+    $params = $context['params'];
     if (isset($params['lastModifiedDate'])) {
       $params['lastModifiedDate'] = (string) $object[$dsid]->createdDate;
     }
@@ -244,6 +245,7 @@ class IslandoraFedoraApiM extends FedoraApiM {
       'params' => $params,
     );
     islandora_alter_object($object, $context);
+    $params = $context['params'];
     try {
       if ($context['block']) {
         throw new Exception('Modify Object was blocked.');