hjælp til mysql_num_rows

Hej alle sammen, jeg har følgende script:

<?php
    if (isset($HTTP_GET_VARS['cID'])) {
      $cID = tep_db_prepare_input($HTTP_GET_VARS['cID']);
      $orders_query_raw = "select o.orders_id, o.customers_name, o.customers_id, o.payment_method, o.date_purchased, o.last_modified, o.currency, o.currency_value, s.orders_status_name, ot.text as order_total from " . TABLE_ORDERS . " o left join " . TABLE_ORDERS_TOTAL . " ot on (o.orders_id = ot.orders_id), " . TABLE_ORDERS_STATUS . " s where o.customers_id = '" . (int)$cID . "' and o.orders_status = s.orders_status_id and s.language_id = '" . (int)$languages_id . "' and ot.class = 'ot_total' order by orders_id DESC";
    } elseif (isset($HTTP_GET_VARS['status'])) {
      $status = tep_db_prepare_input($HTTP_GET_VARS['status']);
      $orders_query_raw = "select o.orders_id, o.customers_name, o.payment_method, o.date_purchased, o.last_modified, o.currency, o.currency_value, s.orders_status_name, ot.text as order_total from " . TABLE_ORDERS . " o left join " . TABLE_ORDERS_TOTAL . " ot on (o.orders_id = ot.orders_id), " . TABLE_ORDERS_STATUS . " s where o.orders_status = s.orders_status_id and s.language_id = '" . (int)$languages_id . "' and s.orders_status_id = '" . (int)$status . "' and ot.class = 'ot_total' order by o.orders_id DESC";
    } else {
      $orders_query_raw = "select o.orders_id, o.customers_name, o.payment_method, o.date_purchased, o.last_modified, o.currency, o.currency_value, s.orders_status_name, ot.text as order_total from " . TABLE_ORDERS . " o left join " . TABLE_ORDERS_TOTAL . " ot on (o.orders_id = ot.orders_id), " . TABLE_ORDERS_STATUS . " s where o.orders_status = s.orders_status_id and s.language_id = '" . (int)$languages_id . "' and ot.class = 'ot_total' order by o.orders_id DESC";
    }
    $orders_split = new splitPageResults($HTTP_GET_VARS['page'], MAX_DISPLAY_SEARCH_RESULTS, $orders_query_raw, $orders_query_numrows);
  if (mysql_num_rows($orders_query_raw)==0) {
      print "<p class=\"dataTableContent\">Der er endnu ingen ordre!</p>";
    } else {
    $orders_query = tep_db_query($orders_query_raw);
    while ($orders = tep_db_fetch_array($orders_query)) {
    if ((!isset($HTTP_GET_VARS['oID']) || (isset($HTTP_GET_VARS['oID']) && ($HTTP_GET_VARS['oID'] == $orders['orders_id']))) && !isset($oInfo)) {
        $oInfo = new objectInfo($orders);
      }

      if (isset($oInfo) && is_object($oInfo) && ($orders['orders_id'] == $oInfo->orders_id)) {
        echo '              <tr id="defaultSelected" class="dataTableRowSelected" onmouseover="rowOverEffect(this)" onmouseout="rowOutEffect(this)" onclick="document.location.href=\'' . tep_href_link(FILENAME_ORDERS, tep_get_all_get_params(array('oID', 'action')) . 'oID=' . $oInfo->orders_id . '&action=edit') . '\'">' . "\n";
      } else {
        echo '              <tr class="dataTableRow" onmouseover="rowOverEffect(this)" onmouseout="rowOutEffect(this)" onclick="document.location.href=\'' . tep_href_link(FILENAME_ORDERS, tep_get_all_get_params(array('oID')) . 'oID=' . $orders['orders_id']) . '\'">' . "\n";
      }

?>
                <td class="dataTableContent"><?php echo '<a href="' . tep_href_link(FILENAME_ORDERS, tep_get_all_get_params(array('oID', 'action')) . 'oID=' . $orders['orders_id'] . '&action=edit') . '">' . tep_image(DIR_WS_ICONS . 'preview.gif', ICON_PREVIEW) . '</a>&nbsp;' . $orders['customers_name']; ?></td>
                <td class="dataTableContent" align="right"><?php echo strip_tags($orders['order_total']); ?></td>
                <td class="dataTableContent" align="center"><?php echo tep_datetime_short($orders['date_purchased']); ?></td>
                <td class="dataTableContent" align="right"><?php echo $orders['orders_status_name']; ?></td>
                <td class="dataTableContent" align="right"><?php if (isset($oInfo) && is_object($oInfo) && ($orders['orders_id'] == $oInfo->orders_id)) { echo tep_image(DIR_WS_IMAGES . 'icon_arrow_right.gif', ''); } else { echo '<a href="' . tep_href_link(FILENAME_ORDERS, tep_get_all_get_params(array('oID')) . 'oID=' . $orders['orders_id']) . '">' . tep_image(DIR_WS_IMAGES . 'icon_info.gif', IMAGE_ICON_INFO) . '</a>'; } ?>&nbsp;</td>
              </tr>
<?php
            }  }
?>
              <tr>
                <td colspan="5"><table border="0" width="100%" cellspacing="0" cellpadding="2">
                  <tr>
                    <td class="smallText" valign="top"><?php echo $orders_split->display_count($orders_query_numrows, MAX_DISPLAY_SEARCH_RESULTS, $HTTP_GET_VARS['page'], TEXT_DISPLAY_NUMBER_OF_ORDERS); ?></td>
                    <td class="smallText" align="right"><?php echo $orders_split->display_links($orders_query_numrows, MAX_DISPLAY_SEARCH_RESULTS, MAX_DISPLAY_PAGE_LINKS, $HTTP_GET_VARS['page'], tep_get_all_get_params(array('page', 'oID', 'action'))); ?></td>
                  </tr>
                </table></td>
              </tr>
            </table></td>


hvor jeg har lagt en "
  if (mysql_num_rows($orders_query_raw)==0) {
print "<p class=\"dataTableContent\">Der er endnu ingen ordre!</p>";
    } else {" ind for at den skal kunne sige til mig når der ingen vare er.

Men jeg får så følgende fejl:

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource.

Hvad mener den ?