General Support: Gallery Search no longer HTML compliant

I've raised a bug (ticket #258), but figured that I'd ask for someone who knows what they're doing to give the 'one-minute-flat' fix (which I'm sure is all it would take to squish a bug like this).

The following code (in plog-functions.php) gives html that is not compliant:

function generate_search_box() {
global $config;

$output = '<form id="plogsearch" action="'.generate_url('search').'" method="get">
<div id="search-box">
<input type="text" id="searchterms" name="searchterms" />
<input class="submit" type="submit" value="'.plog_tr('Search').'" />
</div>';
if (!$config['use_mod_rewrite']) {
$output .= "\n\t\t\t\t\t" . '<input type="hidden" name="level" value="search" />';
if (!empty($config['query_args'])) {
$query = array();
$query_args = explode('&amp;', $config['query_args']);
foreach ($query_args as $value) {
$query = explode('=', $value);
$output .= "\n\t\t\t\t\t" . '<input type="hidden" name="'.$query[0].'" value="'.$query[1].'" />';
}
}
}
$output .= "\n\t\t\t\t" . '</form>' . "\n";

return $output;
}

It's to do with the closing div tag, but I don't know how the code needs to be changed to fix it.

Stuart