Open style/xbtit_default/torrent.details.tpl, find and remove this:
Code:
<if:EXTERNAL>
<tr>
<td valign="middle" align="right" class="header"><tag:torrent.update_url /></td>
<td class="lista" align="center" style="text-align:left;" valign="top"><tag:torrent.announce_url /></td>
</tr>
<tr>
<td valign="middle" align="right" class="header"><tag:language.LAST_UPDATE /></td>
<td class="lista" align="center" style="text-align:left;" valign="top"><tag:torrent.lastupdate /> (<tag:torrent.lastsuccess />)</td>
</tr>
</if:EXTERNAL>