diff --git a/src/applications/conpherence/controller/ConpherenceNewController.php b/src/applications/conpherence/controller/ConpherenceNewController.php
--- a/src/applications/conpherence/controller/ConpherenceNewController.php
+++ b/src/applications/conpherence/controller/ConpherenceNewController.php
@@ -12,6 +12,7 @@
     $message = '';
     $e_participants = null;
     $e_message = null;
+    $errors = array();
 
     // this comes from ajax requests from all over. should be a single phid.
 
@@ -29,10 +30,15 @@
         foreach ($error_codes as $error_code) {
           switch ($error_code) {
             case ConpherenceEditor::ERROR_EMPTY_MESSAGE:
-              $e_message = true;
+              $e_message = pht('Required');
+              $errors[] = pht(
+                'You can not send an empty message.');
               break;
             case ConpherenceEditor::ERROR_EMPTY_PARTICIPANTS:
-              $e_participants = true;
+              $e_participants = pht('Required');
+              $errors[] = pht(
+                'You must choose at least one recipient for your '.
+                'message.');
               break;
           }
         }
@@ -69,6 +75,7 @@
 
     $dialog = id(new AphrontDialogView())
       ->setWidth(AphrontDialogView::WIDTH_FORM)
+      ->setErrors($errors)
       ->setUser($user)
       ->setTitle($title)
       ->addCancelButton($cancel_uri)