Breadcrumb mystery

Some day, I'm going to have the time to migrate to the real Drupal 6 site, but meanwhile, back at the loony bin:

I'm having trouble with my breadcrumbs on one section of my site and nowhere else-- child pages in http://naturalsciences.org/nature-research-center show Home and the current page, but not the parent (nature-research-center) page, i.e. the How Do We Know page would show:

"Home > How Do We Know" instead of:

"Home > Nature Research Center > How Do We Know"

The grandchildren pages are also missing the Nature Research Center & their parent links are bad because they're missing the nature-research-center part of the path, i.e.

"Home > How Do We Know > Dinochicken" where "How Do We Know" tries to go to the non-existent "/how-do-we-know" instead of "/nature-research-center/how-do-we-know". I checked and the term hierarchy is correct.

A quick look at the installed modules shows Custom Breadcrumbs and Taxonomy Breadcrumb are both installed but neither is enabled-- I'm afraid it's another FrankenDrupal issue. I hate to ask, but could anybody take a look at this?

I'm not sure where to start, but these looked like the most relevant bits of code:

From page.tpl.php:

        <div id="breadcrumbs_bar"> 
<?php
 echo breadcrumbs($GLOBALS[current_nid]); 
?>
 </div>

From template.php:

        /* Theme override for theme_breadcrumb
        * Adds title of current page to end of breadcrumb
        */

        function newTheme_breadcrumb($breadcrumb) {
          if (!empty($breadcrumb)) {
            //Append title of current page
            $breadcrumb[] = drupal_get_title();
               return ''. implode(' > ', $breadcrumb);
          }
        }



        if(!function_exists(breadcrumbs)){function breadcrumbs($nid, $path = null){
            global $m_data;
            global $user;

        if(!$path)
        $path = $m_data[levels];
        if(!is_array($path))
        $path = explode("/", $path);


        //create level names (used in bcrumbs)
            $current_level = end(array_keys($path));
            $terms = get_tax($m_data[tax]);
            foreach ($path as $key=>$level){
                foreach($terms as $term){

        if(make_url($level) == make_url($term[name]))
        //$test = make_url($level).' | '.make_url($term[name]);
        $m_data[levels_name][$key] = make_name($term[name]);
    }
}

$build2=null;
$build2=
'<a href="/">Home</a>';
    $build = null; $href = null;
    foreach($path as $key=>$level){
    if($m_data[levels_name][$key]){
        if($level==end($path)){
        $build .= '&nbsp;&gt;&nbsp;'.$m_data[levels_name][$key];
        } else {
        $href .='/'.make_url($level);
        $build .= ' &gt; <a href="'.$href.'">'.$m_data[levels_name][$key].'</a>';
        }
        } 
    }
$build2 = '<div id="breadcrumbs">'.$build2.$build.'</div>';

if($m_data[levels][0]!="print" and $m_data[levels][0]!="edits"){

    $printpath = $_SERVER['REQUEST_URI'].'/?print=this';

    if(substr_count($printpath, '?')>1)
    $printpath = $_SERVER['REQUEST_URI'].'&print=this';

    $build2 .=
    '<div id="print">'.
    '<a target="_blank" href="'.$printpath.'">Print this Page</a>'.
    '</div>';
}

return $build2.$test;
        }}