CKeditor error with IE8 when opening image manager

function get_ckeditor()
{
    require_once(DIR_FS_ADMIN . 'ckeditor/ckeditor.php');
    require_once(DIR_FS_ADMIN . 'ckfinder/ckfinder.php');
    $CKEditor = new CKeditor();
    $CKEditor->basePath = HTTP_SERVER .  'ckeditor/';
    $CKEditor->returnOutput = true;
    $ckfinder = new CKFinder();
    $ckfinder->BasePath = DIR_WS_ADMIN . 'ckfinder/';
    $ckfinder->SetupCKEditorObject($CKEditor);
    return $CKEditor;
}

$CKEditor = get_ckeditor();
    $config = array();
    $config['toolbar'] = array(array('Image'));
    if ($height > 0)
        $CKEditor->config['height'] = $height;
    if ($width > 0)
        $CKEditor->config['width'] = $width;

    if ($text != '')
    {
        if (!$filter_text)
        {
            $text = '<img src="' . DIR_WS_CATALOG_IMAGES . $text . '" alt="" />';
        }
        else
            $text = html_entity_decode(stripslashes($text)); //Utile pour tep_cfg_logo

    }

    $field = $CKEditor->editor($name, $text, $config);
    echo $field;