--- invite.module	2009-03-25 09:35:36.000000000 -0600
+++ invite_new.module	2009-03-25 09:37:05.000000000 -0600
@@ -902,7 +902,9 @@ function invite_form_validate($form, &$f
         $error .= implode(', ', $failed_emails);
         drupal_set_message($error, 'error');
       }
+    }
 
+    if($emails) {
       // Filter out already invited users, but pass validation.
       $failed_emails = _invite_validate_emails("SELECT email FROM {invite} WHERE email IN (". db_placeholders($emails, 'varchar') .") AND uid = %d AND canceled = 0", $emails, $user->uid);
       if (count($failed_emails)) {
@@ -910,6 +912,7 @@ function invite_form_validate($form, &$f
         $error .= implode(', ', array_map('check_plain', $failed_emails));
         drupal_set_message($error, 'error');
       }
+    }
 
       // Check that there is at least one valid e-mail remaining after filtering
       // out dupes.
@@ -929,7 +932,6 @@ function invite_form_validate($form, &$f
         form_set_error('email', t('You cannot send more than one invitation.'));
         return;
       }
-    }
   }
 
   // Save valid emails.