Warning: mysql_fetch_assoc():

Bonjour,
Je suis vraiment un débutant et j'ai vraiment besoins de votre aide. J'ai ce message qui s'affiche:
Warning: mysql_fetch_assoc(): supplied argument is not a valid MySQL result resource in c:\program files\easyphp1-8\www\ism-dakar.com\class\cycle.php on line 89

Warning: mysql_free_result(): supplied argument is not a valid MySQL result resource in c:\program files\easyphp1-8\www\ism-dakar.com\class\cycle.php on line 93


Voici tout le code de la page:
<?php
class cycle
{
var $id_cycle="";
var $cycle="";
/**
* Constructeur de la classe cycle
* @access public
*/
function cycle($id_cycle="", $cycle="")
{
$this->id_cycle=$id_cycle;
$this->cycle=$cycle;
}
/**
* La function get_id_cycle qui retourne l'attribut id_cycle
* @access public
*/
function get_id_cycle()
{
return $this->id_cycle;
}
/**
* La functions set_id_cycle qui modifie l'attribut id_cycle
* @access public
*/
function set_id_cycle($id_cycle="")
{
$this->id_cycle=$id_cycle;
}
/**
* La function get_cycle qui retourne l'attribut cycle
* @access public
*/
function get_cycle()
{
return $this->cycle;
}
/**
* La functions set_cycle qui modifie l'attribut cycle
* @access public
*/
function set_cycle($cycle="")
{
$this->cycle=$cycle;
}
/**
* La function Ajout d'un(e) offre
* @access public
*/
function ajouter_cycle()
{
$sql ="INSERT INTO ";
$sql .="cycle ";
$sql .="(`id_cycle`, `cycle`) ";
$sql .="VALUES ('', '".htmlentities($this->cycle, ENT_QUOTES)."')";
$insert=mysql_query($sql);
if($insert)
return mysql_insert_id();
else return 0;
}
/**
* La function modification d'un(e) cycle
* @access public
*/
function update_cycle()
{
$sql ="UPDATE ";
$sql .="cycle ";
$sql .="SET ";
$sql .="cycle='".htmlentities($this->cycle, ENT_QUOTES)."' ";
$sql .="WHERE id_cycle='".$this->id_cycle."'";
$requete = mysql_query($sql);
if ($requete) return 1;
else return 0;
}
/**
* La function lire tout(e)es les cycle
* @access public
*/
function select_cycle()
{
$sql ="SELECT ";
$sql .="* ";
$sql .="FROM cycle ";
$sql .="ORDER BY cycle ";
$requete = mysql_query($sql);
$tmp=array();
WHILE($row = mysql_fetch_assoc($requete))
{
array_push($tmp,$row);
}
mysql_free_result($requete);
return $tmp;
}
/**
* La function lire tout(e)s les cycle limité par un cyclebre
* @access public
*/
function select_cycle_limite_nombre($limite, $nombre, $monotonie)
{
$sql ="SELECT ";
$sql .="* ";
$sql .="FROM cycle ";
if($monotonie == 1)
{
$sql .="ORDER BY cycle ";
$sql .="DESC ";
}
else if ($monotonie == 2)
{
$sql .="ORDER BY cycle ";
}
else
{
$sql .="ORDER BY id_cycle ";
}
$sql .="LIMIT ".$limite.",".$nombre;
$requete = mysql_query($sql);
$tmp=array();
WHILE($row = mysql_fetch_assoc($requete))
{
array_push($tmp,$row);
}
return $tmp;
}
/**
* La function lire d'un(e) offre suivant id_cycle
* @access public
*/
function select_cycle_by_id_cycle()
{
$sql ="SELECT ";
$sql .="* ";
$sql .="FROM cycle ";
$sql .="WHERE id_cycle = '".$this->id_cycle."' ";
$sql .="ORDER BY id_cycle ";
$select=mysql_query($sql);
$tmp=array();
WHILE($row = mysql_fetch_assoc($select))
{
array_push($tmp,$row);
}
return $tmp;
}
/**
* La function supprimer tou(te)s les cycle
* @access public
*/
function delete_cycle()
{
$sql ="DELETE ";
$sql .="FROM cycle ";
$delete=mysql_query($sql);
if($delete) return 1;
else return 0;
}
/**
* La function supprimer d'un(e) cycle suivi id_cycle
* @access public
*/
function delete_cycle_by_id_cycle()
{
$sql ="DELETE ";
$sql .="FROM cycle ";
$sql .="WHERE id_cycle = ".$this->id_cycle;
$delete=mysql_query($sql);
if($delete) return 1;
else return 0;
}
}
?>
</body>
</html>

Merci