no puedo exportar a pdf

[ferbux]

Hola tengo un problema al tratar de exportar el resultado alojado en una tabla en mysql, todo funciona bien cuando solo se llena 1 hoja del archivo exportado en pdf pero cuando los registros son demasiados para caber en una hoja de pdf y ocupan otra me marca este error:

Fatal error: Call to a member function on a non-object in D:\Home\Aplicaciones\AlpineHtdocs\alpine\modules\C trlHoraspedido\pdfextendsfpdf_hrs_d.php on line 290

esto es lo ke tengo en mi archivo pdfextendsfpdf_hrs_d.php cerca de esa linea:

Código:

 function Header()
    {
        $this->SetMargins(5,6);
        $this->SetAutoPageBreak(1,0);
        $this->SetFont('Arial','BI',6);
        $this->SetFillColor(90,200,250);
        $this->SetXY(250,205);
        $this->Cell(20,3,"Página ".$this->PageNo()." de {nb}",0,0,"R",1);
        $this->SetMargins(5,12);
        $this->SetAutoPageBreak(1,10);
        $this->SetXY(5,12);
        $this->SetFont('Arial','BI',8);
        if ($this->PageNo()>1) {
    
    
	$this->SetXY(5,5);                $pdf->HCell(5,6,"",0,0,"C",1);               
	$this->SetX($this->GetX()+1);     $this->HCell(5,6,"pedido",0,0,"C",1);
	$this->SetX($this->GetX()+1);     $this->HCell(9,6,"descrp",0,0,"C",1);
    $this->SetX($this->GetX()+1);     $this->HCell(7,6,"grupo",0,0,"C",1);
    $this->SetX($this->GetX()+1);     $this->HCell(7,6,"39Dir",0,0,"C",1);
    $this->SetX($this->GetX()+1);     $this->HCell(30,6,"40Dir",0,0,"C",1);
    $this->SetX($this->GetX()+1);     $this->HCell(7,6,"41Dir",0,0,"C",1);
    $this->SetX($this->GetX()+1);     $this->HCell(3,6,"42Dir",0,0,"C",1);
    $this->SetX($this->GetX()+1);     $this->HCell(29,6,"43Dir",0,0,"C",1);
    $this->SetX($this->GetX()+1);     $this->HCell(5,6,"44Dir",0,0,"C",1);
    $this->SetX($this->GetX()+1);     $this->HCell(5,6,"45Dir",0,0,"C",1);
	$this->SetX($this->GetX()+1);     $this->HCell(2,6,"46Dir",0,0,"C",1);
    $this->SetX($this->GetX()+1);     $this->HCell(15,6,"50Dir",0,0,"C",1);
    $this->SetX($this->GetX()+1);     $this->HCell(4,6,"51Dir",0,0,"C",1);
	$this->SetX($this->GetX()+1);     $this->HCell(39,6,"52Dir",0,0,"C",1);
    $this->SetX($this->GetX()+1);     $this->HCell(5,6,"53Dir",0,0,"C",1);
	$this->SetX($this->GetX()+1);     $this->HCell(19,6,"54Dir",0,0,"C",1);
    $this->SetX($this->GetX()+1);     $this->HCell(5,6,"55Dir",0,0,"C",1);
	$this->SetX($this->GetX()+1);     $this->HCell(5,6,"70Dir",0,0,"C",1);
    $this->SetX($this->GetX()+1);     $this->HCell(5,6,"71Dir",0,0,"C",1);
	$this->SetX($this->GetX()+1);     $this->HCell(5,6,"75Dir",0,0,"C",1);
    $this->SetX($this->GetX()+1);     $this->HCell(5,6,"TotDir",0,0,"C",1);

			
			
            $this->SetXY(5,12+($_y2<$_y3?$_y2:$_y2));
        }
    }
}
?>

mi linea 290 es la ke marco con negritas. Ojala alguien me pueda orientar un poco, Salu2 y gracias de antemano.