You missed removing a "." after echo:
PHP Code:
<div id="logo"><?php echo. zen_image($template->get_template_dir(HEADER_LOGO_IMAGE, DIR_WS_TEMPLATE, $current_page_base,'images'). '/' . HEADER_LOGO_IMAGE, HEADER_ALT_TEXT) ; ?></div>
Not sure if that's the whole problem, but it is a problem.