Problems with Javascript and external.php

[cyburbia]

I've been trying to use the external Javascript feature to place a list of the most recently updated threads on my non-vB index page.

The code of http://www.cyburbia.org/java.html , a test page I'm using for the Javascript recommended on this site is ...

<script type="text/javascript" src="http://www.cyburbia.org/forums/external.php?type=js"></script> 
  <script type="text/javascript">
  <!--
  for (i = 0; i < 15; i++)
  {
  document.writeln("<b><a 
 href=\"http://www.cyburbia.org/forums/showthread.php?threadid="+threads[i].threadid+"\">"+threads[i].title+"</a></b>&nbsp;&nbsp;By: 
  <i>"+threads[i].poster+"</i><br />");
  }
  //-->
  </script>

The code is the same as in examples given in other vBulletin threads on the topic.

External Javascript is enabled in the vBulletin options.

While the feed seems to be working (see http://www.cyburbia.org/forums/external.php?type=js ), the array won't parse into readable HTML. The test page, using supposedly proven code as posted on other threads here (again, http://www.cyburbia.org/java.html ), just isn't working.

Anyone know what I'm doing wrong?