True...Most likely the body tags won't disrupt your code, but it just looks out of place. You can't delete the "head" tags or the inner codes won't function properly or give an error such as that in your case. Example of multiple "body" tags...Currently when I click "view source" in your public_forum_summary.pl I found:
[/code]with second "head" after that. Then I found:
</pre></div></div>Then I found:<br><br> [code]
which has your TimeZone code. You also have multiple "head" tags all over the place. I really do not know how much of an effect this will have on your board but I would think that potentially it can disrupt the functions of your page.
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Now probably someone with a background in javascript would be able to help you with your TimeZone code but a friend of mine who does the server side for our site said that more than likely when codes clash it has to do with the way it's written. If you were to create an "iframe" for your TimeZone code my hunch is that both the NewsFader and TimeZone codes will work together. For both of the codes to work on the same page without frames I think one of them have to be adjusted...If not then you'll just need to find another code that will work.