diff -urp calendar.original/includes/calendar_plugin_display_attachment.inc calendar/includes/calendar_plugin_display_attachment.inc
--- calendar.original/includes/calendar_plugin_display_attachment.inc	2009-03-18 05:03:36.000000000 +1100
+++ calendar/includes/calendar_plugin_display_attachment.inc	2009-09-25 12:55:19.000000000 +1000
@@ -161,10 +161,12 @@ class calendar_plugin_display_attachment
    */
   function options(&$display) {
     parent::options($display);
-    $display->display_options['inherit_argments'] = TRUE;
-    $display->display_options['inherit_filters'] = TRUE;
-    $display->display_options['attachment_position'] = 'after';
-    $display->display_options['calendar_type'] = $this->calendar_type();
+    if(is_object($display)) {
+      $display->display_options['inherit_argments'] = TRUE;
+      $display->display_options['inherit_filters'] = TRUE;
+      $display->display_options['attachment_position'] = 'after';
+      $display->display_options['calendar_type'] = $this->calendar_type();
+    }
   }  
 
   /**
diff -urp calendar.original/includes/calendar_plugin_display_block.inc calendar/includes/calendar_plugin_display_block.inc
--- calendar.original/includes/calendar_plugin_display_block.inc	2008-12-07 01:56:15.000000000 +1100
+++ calendar/includes/calendar_plugin_display_block.inc	2009-09-25 12:55:30.000000000 +1000
@@ -47,15 +47,17 @@ class calendar_plugin_display_block exte
 
   function options(&$display) {
     parent::options($display);
-    $display->display_options['displays'] = array();
-    $display->display_options['style_plugin'] = 'calendar_nav';
-    $display->display_options['items_per_page'] = 0;
-    $display->display_options['row_plugin'] = '';
-    $display->display_options['defaults']['style_plugin'] = FALSE;
-    $display->display_options['defaults']['style_options'] = FALSE;
-    $display->display_options['defaults']['items_per_page'] = FALSE;
-    $display->display_options['defaults']['row_plugin'] = FALSE;
-    $display->display_options['defaults']['row_options'] = FALSE;
+    if (is_object($display)) {
+      $display->display_options['displays'] = array();
+      $display->display_options['style_plugin'] = 'calendar_nav';
+      $display->display_options['items_per_page'] = 0;
+      $display->display_options['row_plugin'] = '';
+      $display->display_options['defaults']['style_plugin'] = FALSE;
+      $display->display_options['defaults']['style_options'] = FALSE;
+      $display->display_options['defaults']['items_per_page'] = FALSE;
+      $display->display_options['defaults']['row_plugin'] = FALSE;
+      $display->display_options['defaults']['row_options'] = FALSE;
+    }
   } 
   
   function option_definition () {
diff -urp calendar.original/includes/calendar_plugin_display_page.inc calendar/includes/calendar_plugin_display_page.inc
--- calendar.original/includes/calendar_plugin_display_page.inc	2009-07-25 05:44:09.000000000 +1000
+++ calendar/includes/calendar_plugin_display_page.inc	2009-09-25 12:55:42.000000000 +1000
@@ -44,15 +44,17 @@ class calendar_plugin_display_page exten
 
   function options(&$display) {
     parent::options($display);
-    $display->display_options['displays'] = array();
-    $display->display_options['style_plugin'] = 'calendar_nav';
-    $display->display_options['items_per_page'] = 0;
-    $display->display_options['row_plugin'] = '';
-    $display->display_options['defaults']['style_plugin'] = FALSE;
-    $display->display_options['defaults']['style_options'] = FALSE;
-    $display->display_options['defaults']['row_plugin'] = FALSE;
-    $display->display_options['defaults']['row_options'] = FALSE;
-    $display->display_options['defaults']['items_per_page'] = FALSE;
+    if (is_object($display)) {
+      $display->display_options['displays'] = array();
+      $display->display_options['style_plugin'] = 'calendar_nav';
+      $display->display_options['items_per_page'] = 0;
+      $display->display_options['row_plugin'] = '';
+      $display->display_options['defaults']['style_plugin'] = FALSE;
+      $display->display_options['defaults']['style_options'] = FALSE;
+      $display->display_options['defaults']['row_plugin'] = FALSE;
+      $display->display_options['defaults']['row_options'] = FALSE;
+      $display->display_options['defaults']['items_per_page'] = FALSE;
+    }
   } 
   
   function option_definition () {