obj con array pasado a SESSION

[marcwolf]

hola,
Hago lo siguiente.
ProjectClass

Código:

private function loadTasks(){
        $bd = $_SESSION['bd'];
        // load all tasks of the project
        $TaskClass = new TaskClass(1,2, 3, 4, 5);
         // Cargo de  mysql  a l'array de objctsTaskClass .a on parentid=0 osea el padre sin padre.
 $dataset = $bd->loadMainTasks($this->getProjectId());
while ($registro = mysql_fetch_array($dataset)) {
    $this->createMainTask(0,$registro['name'], $registro['initialdate'], $registro['enddate'], $registro['desc']);
            }
// Cargo de  mysql  a l'array de objctsTaskClass .a on parentid=x osea el padre con padre/s.
 $dataset = $bd->loadTask($this->getProjectId());
 $TaskClass = new TaskClass(1,2,3,4,5);
 while ($registro = mysql_fetch_array($dataset)) {
     if($registro['parentid'] !="0"){
  $TaskClass->addChild($registro['parentid'],$registro['name'],$registro['initialdate'], $registro['enddate'], $registro['desc']);
     }
 }
    }

Donde llamo los métodos.

Código:

$ProjectClass = $_SESSION["ProjectClass"];
$PoorChilds = $ProjectClass->getArrayOfTask();
echo $PoorChilds[0]->getNameProject();

Pero me sale el siguiente error:

Código:

Fatal error: main() [<a href='function.main'>function.main</a>]: 
The script tried to execute a method or access a property of an incomplete object.
 Please ensure that the class definition &quot;TaskClass&quot; of the object you are trying to operate on 
was loaded _before_ unserialize() gets called or provide a __autoload() function to load the class definition 
in E:\EasyPHP-5.3.6.0\www\Exam\pages\homepageC2.php on line 28

Gracias de antemano