20100427 update -- It happened again, with the same short <ul> tag block disappearing. Persistent gremlin, it is. So, I've tried this: inside the content area of the <ul>/</ul> pair, I have inserted a forced space ("&nbsp;"). We'll see.

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This has actually occurred more than once. The Java error was <<document.getElementById("twitter_update_list") is null>>. The error was caused by gremlins, as far as I can tell. Or perhaps by an edit of the Twitter block.

Anyway, a little perusing of an archived version of the block (you do always keep copies of your code OFF of the site, right?) revealed that a short ID element had gone missing. Right after the div tag for the twitter content there should be another tag pair with the id "twitter_update_list". This is encased in a ul tag on the site, but I suppose it could be a span tag, as well. Anyway, putting this tag pair -- <ul id="twitter_update_list"></ul> -- right after the initial div -- <div id="twitter_div"> -- fixes the problem.

Here's the full twitter block code for the ORP, as of today:

<div id="twitter_div">
<ul id="twitter_update_list"></ul>
<a href="http://twitter.com/orgopcommoffice" id="twitter-link" style="display: block; text-align: right;">Follow the ORP on Twitter</a></div>
<script type="text/javascript" src="http://twitter.com/javascripts/blogger.js"></script>
<script type="text/javascript" src="http://twitter.com/statuses/user_timeline/orgopcommoffice.json?callback=twitterCallback2&amp;count=3"></script>
</div>