--- node.module.old	2007-02-23 04:01:21.000000000 -0500
+++ node.module	2007-02-23 04:19:32.000000000 -0500
@@ -593,6 +593,10 @@ function node_save(&$node) {
     $revisions_table_values['log'] = $node->log;
     $revisions_table_types['log'] = "'%s'";
   }
+  else {
+    $revisions_table_values['log'] = ''; // empty string value
+    $revisions_table_types['log'] = "'%s'";
+  }
   $node_table_values = array('nid' => $node->nid, 'vid' => $node->vid,
                     'title' => $node->title, 'type' => $node->type, 'uid' => $node->uid,
                     'status' => $node->status, 'created' => $node->created,