Probably should do this over on ubbdev since it's a base code modification but it's pretty small.

You'd need to edit the file libs/html.inc.php. About line 260 is where the category is added to the breadcrumbs and you could just comment that out:

PHP Code

	  $breadcrumb .=  " &raquo; <a href=\"" . make_ubb_url("ubb=cfrm&c=$category", $tree['categories'][$category], false) . "\">{$tree['categories'][$category]}</a>";