=== modified file 'wysiwyg.module'
--- wysiwyg.module	2009-03-10 20:11:45 +0000
+++ wysiwyg.module	2009-05-14 19:41:49 +0000
@@ -60,7 +60,7 @@
   $form['#after_build'][] = 'wysiwyg_process_form';
   // Blog module in Drupal 5 uses a wrong/unusual form element key for the input
   // format selector.
-  if ($form_id == 'blog_node_form') {
+  if ($form_id == 'blog_node_form' && module_exists('blog')) {
     $form['body_filter']['format'] = $form['body_filter']['filter'];
     unset($form['body_filter']['filter']);
   }