Font Error When Export To Pdf File

Hi all,

I have a mistake when export data to pdf file,

$student = Students::model()->findByAttributes(array('id'=>$_REQUEST['id']));


	$student = $student->first_name.' '.$student->last_name.' Profile.pdf';


    $pdf = Yii::app()->ePdf->mpdf('', 'A4', 0, 'Tahoma', 2, 2, 2, 2);





    try {


        $pdf->AddPage('L');


        $pdf->useAdobeCJK = true;


        $pdf->cacheTables = false;


       // $pdf->layout = 'myview';


        //$mylayout = new myview();


        $pdf->WriteHTML($this->renderPartial('myprintpdf', array('model'=>$this->loadModel($_REQUEST['id'])),true, false));


        $pdf->Output($student, 'D');


    } catch (Exception $exc) {


        echo $exc->getTraceAsString();


    }

when i run this function, the pdf file was create have some char not in utf-8 standard, what should i do now?