diff -r f5718d7c2a6a -r ec90736b9cb9 includes/clientside/static/ajax.js
--- a/includes/clientside/static/ajax.js	Sun Feb 17 20:19:17 2008 -0500
+++ b/includes/clientside/static/ajax.js	Mon Feb 18 16:27:28 2008 -0500
@@ -185,7 +185,9 @@
   enableUnload();
   setAjaxLoading();
   ajaxGet(stdAjaxPrefix+'&_mode=getpage&noheaders', function() {
-    if ( ajax.readyState == 4 && ajax.status == 200 ) {
+    // Allow for 404 here, it's generated by the "page not found" error message
+    // (even with noheaders specified, probably should be fixed)
+    if ( ajax.readyState == 4 && ( ajax.status == 200 || ajax.status == 404 ) ) {
       unsetAjaxLoading();
       document.getElementById('ajaxEditContainer').innerHTML = ajax.responseText;
       selectButtonMajor('article');