--- commentactivity.module
+++ (clipboard)
@@ -109,13 +109,12 @@
         // This is all the information you'll need later in order to build
         // the activity message.
         $user = user_load(array('uid' => $a1['uid']));
-        $content_types = node_get_types();
         $data = array(
           'author-uid' => $user->uid,
           'subject' => l($a1['subject'], 'node/'. $node->nid, array(), NULL, 'comment-'. $a1['cid']),
           'parent-node' => l($node->title, 'node/'. $node->nid),
           'parent-node-author' => theme('username', $node_author),
-          'parent-node-type' => $content_types[$node->type]->name,
+          'parent-node-type' => $node->type,
         );
 
         $target_users_roles = array();
@@ -132,7 +131,7 @@
 
         $target_users_roles = array(
           ACTIVITY_ALL => 'all',
-          $node->uid => 'parent_node_author',
+          $node->uid => 'parent node author',
           // and the most important role is 'author' so we add it last.
           $a1['uid'] => 'author',
         );