Error in your SQL syntax

CREATE TABLE IF NOT EXISTS `forum_present` (
  `id_membre` int(10) NOT NULL,
  `id_forum` varchar(20) collate latin1_bin NOT NULL,
  `id_topic` varchar(10) collate latin1_bin NOT NULL,
  `pseudo` varchar(20) collate latin1_bin NOT NULL,
  `date` date NOT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_bin;

echo '<td>';
$query = 'SELECT id_membre 
          FROM forum_present 
          WHERE id_membre = '.intval($_SESSION['id']);

$result = mysql_query($query) or exit(mysql_error());
if (mysql_num_rows($result) <> 0)
{

      $query_insert = '
          INSERT INTO forum_present
          (id_forum, id_membre, pseudo, date)
          VALUES ("' . $forum . '", "' . $_SESSION ['id'] . '", "' . $_SESSION['login'] . '", "' . time() . '")
          ';
          mysql_query($query_insert) or exit (mysql_error());
   }
   else
   {
     $query_update2 = '
          UPDATE forum_present
          SET date="' . time() . '", id_topic="'. $topic .'"
          WHERE id_membre="' . $_SESSION['id'] . '"
          ';
          mysql_query($query_update2) or exit (mysql_error());
   }



//pour supprimer le membre si il n'est plus là:


$query_member = '
SELECT id_membre, pseudo, id_forum,date 
FROM forum_present 
WHERE id_forum='.$forum;
$result = mysql_query($query_member) or exit (mysql_error());
while($do = mysql_fetch_array($result))
{
echo' <a href="http://tonlien">'.$this->coder_texte($do['pseudo']).'</a>';
}
echo'</td></tr>'; 
echo'</table>';
$expected_time = time() - 60 * 3;
   $query_delete = '
   DELETE FROM forum_present
   WHERE date < ' . $expected_time . '
   ';
   mysql_query($query_delete) or exit (mysql_error());

		}
		}

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 3