diff --git a/plugins/calendar/calendar.php b/plugins/calendar/calendar.php
index a71d9cd4..661ede94 100644
--- a/plugins/calendar/calendar.php
+++ b/plugins/calendar/calendar.php
@@ -494,8 +494,10 @@ class calendar extends rcube_plugin
     
     if ($success)
       $this->rc->output->show_message('successfullysaved', 'confirmation');
-    else
-      $this->rc->output->show_message('calendar.errorsaving', 'error');
+    else {
+      $error_msg = $this->gettext('errorsaving') . ($this->driver->last_error ? ': ' . $this->driver->last_error :'');
+      $this->rc->output->show_message($error_msg, 'error');
+    }
 
     // TODO: keep view and date selection
     if ($success && $reload)
diff --git a/plugins/calendar/drivers/calendar_driver.php b/plugins/calendar/drivers/calendar_driver.php
index d5015a2d..8b35f6ad 100644
--- a/plugins/calendar/drivers/calendar_driver.php
+++ b/plugins/calendar/drivers/calendar_driver.php
@@ -82,6 +82,7 @@ abstract class calendar_driver
   public $undelete = false; // event undelete action
   public $categoriesimmutable = false;
   public $alarm_types = array('DISPLAY');
+  public $last_error;
 
   /**
    * Get a list of available calendars from this source
diff --git a/plugins/calendar/drivers/kolab/kolab_driver.php b/plugins/calendar/drivers/kolab/kolab_driver.php
index 50792db7..9a77f1a0 100644
--- a/plugins/calendar/drivers/kolab/kolab_driver.php
+++ b/plugins/calendar/drivers/kolab/kolab_driver.php
@@ -221,15 +221,18 @@ class kolab_driver extends calendar_driver
     }
     // sanity checks (from steps/settings/save_folder.inc)
     else if (!strlen($folder)) {
+      $this->last_error = 'Invalid folder name';
       return false;
     }
     else if (strlen($folder) > 128) {
+      $this->last_error = 'Folder name too long';
       return false;
     }
     else {
       // these characters are problematic e.g. when used in LIST/LSUB
       foreach (array($delimiter, '%', '*') as $char) {
         if (strpos($folder, $delimiter) !== false) {
+          $this->last_error = 'Invalid folder name';
           return false;
         }
       }
@@ -254,20 +257,24 @@ class kolab_driver extends calendar_driver
       if ($parent_opts['namespace'] != 'personal'
         && (empty($parent_opts['rights']) || !preg_match('/[ck]/', implode($parent_opts)))
       ) {
+        $this->last_error = 'No permission to create folder';
         return false;
       }
     }
 
     // update the folder name
     if (strlen($oldfolder)) {
-      if ($oldfolder != $folder)
-        $result = rcube_kolab::folder_rename($oldfolder, $folder);
+      if ($oldfolder != $folder) {
+        if (!($result = rcube_kolab::folder_rename($oldfolder, $folder)))
+          $this->last_error = rcube_kolab::$last_error;
+      }
       else
         $result = true;
     }
     // create new folder
     else {
-      $result = rcube_kolab::folder_create($folder, 'event', false);
+      if (!($result = rcube_kolab::folder_create($folder, 'event', false)))
+        $this->last_error = rcube_kolab::$last_error;
     }
 
     return $result ? $folder : false;
@@ -291,6 +298,8 @@ class kolab_driver extends calendar_driver
         $this->rc->user->save_prefs($prefs);
         return true;
       }
+      else
+        $this->last_error = rcube_kolab::$last_error;
     }
 
     return false;
diff --git a/plugins/kolab_core/rcube_kolab.php b/plugins/kolab_core/rcube_kolab.php
index a97512e9..d5b87c51 100644
--- a/plugins/kolab_core/rcube_kolab.php
+++ b/plugins/kolab_core/rcube_kolab.php
@@ -26,6 +26,8 @@ require_once 'Horde/Perms.php';
  */
 class rcube_kolab
 {
+    public static $last_error;
+    
     private static $horde_auth;
     private static $config;
     private static $ready = false;
@@ -254,6 +256,7 @@ class rcube_kolab
         $result = $folder->delete();
 
         if (is_a($result, 'PEAR_Error')) {
+            self::$last_error = $result->getMessage();
             return false;
         }
 
@@ -283,6 +286,7 @@ class rcube_kolab
         ));
 
         if (is_a($result, 'PEAR_Error')) {
+            self::$last_error = $result->getMessage();
             return false;
         }
 
@@ -306,6 +310,7 @@ class rcube_kolab
 
         $result = $kolab->rename($folder);
         if (is_a($result, 'PEAR_Error')) {
+            self::$last_error = $result->getMessage();
             return false;
         }