Index: privatemsg.pages.inc
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/privatemsg/privatemsg.pages.inc,v
retrieving revision 1.1.2.29
diff -u -p -r1.1.2.29 privatemsg.pages.inc
--- privatemsg.pages.inc	7 Oct 2010 00:25:14 -0000	1.1.2.29
+++ privatemsg.pages.inc	11 Oct 2010 19:32:01 -0000
@@ -292,8 +292,12 @@ function privatemsg_new($form, &$form_st
     if (isset($form_state['values']['recipient'])) {
       $recipients_plain = $form_state['values']['recipient'];
     }
-    $subject   = $form_state['values']['subject'];
-    $body      = $form_state['values']['body'];
+    if (isset($form_state['values']['subject'])) {
+      $subject   = $form_state['values']['subject'];
+    }
+    if (isset($form_state['values']['body'])) {
+      $body      = $form_state['values']['body'];
+    }
   }
   if (!$thread_id && !empty($recipients_plain)) {
     drupal_set_title(t('Write new message to @recipient', array('@recipient' => $recipients_plain)));