Preview doesn't display anything but the custom page is effective and works : Preview problem

I'm building an event site. A view is displaying the schedule with speakers. Those speakers name are appearing as link which will at clicking will trigger a modal frame in which my custome page will be displayed.

Basically I have a content type speaker and at http://mysite/node/nid/modal my custom page is displayed.

Speaker = { Title for the name, Body for the Bio, Position in company, company name }

Everything works. (Good) but not the preview.

Here is the exported code of the custom page.

$page = new stdClass;
$page->disabled = FALSE; /* Edit this to true to make a default page disabled initially */
$page->api_version = 1;
$page->name = 'speaker_in_modal';
$page->task = 'page';
$page->admin_title = 'Speaker in modal frame';
$page->admin_description = '';
$page->path = 'node/%node/modal';
$page->access = array();
$page->menu = array();
$page->arguments = array(
  'node' => array(
    'id' => 1,
    'identifier' => 'Node: ID',
    'name' => 'nid',
    'settings' => array(),
  ),
);
$page->conf = array();
$page->default_handlers = array();
$handler = new stdClass;
$handler->disabled = FALSE; /* Edit this to true to make a default handler disabled initially */
$handler->api_version = 1;
$handler->name = 'page_speaker_in_modal_panel_context';
$handler->task = 'page';
$handler->subtask = 'speaker_in_modal';
$handler->handler = 'panel_context';
$handler->weight = 0;
$handler->conf = array(
  'title' => 'Layout for Speaker ID card in modal',
  'no_blocks' => 1,
  'pipeline' => 'standard',
  'css_id' => '',
  'css' => '',
  'contexts' => array(),
  'relationships' => array(),
  'access' => array(
    'plugins' => array(
      0 => array(
        'name' => 'node_type',
        'settings' => array(
          'type' => array(
            'speaker' => 'speaker',
          ),
        ),
        'context' => 'argument_nid_1',
        'not' => FALSE,
      ),
    ),
    'logic' => 'and',
  ),
);
$display = new panels_display;
$display->layout = 'twocol_stacked';
$display->layout_settings = array();
$display->panel_settings = array(
  'style_settings' => array(
    'default' => NULL,
    'top' => NULL,
    'left' => NULL,
    'right' => NULL,
    'bottom' => NULL,
  ),
);
$display->cache = array();
$display->title = '';
$display->content = array();
$display->panels = array();
  $pane = new stdClass;
  $pane->pid = 'new-1';
  $pane->panel = 'left';
  $pane->type = 'content_field';
  $pane->subtype = 'field_photo';
  $pane->shown = TRUE;
  $pane->access = array();
  $pane->configuration = array(
    'label' => 'normal',
    'formatter' => '256width_default',
    'context' => 'argument_nid_1',
    'override_title' => 0,
    'override_title_text' => '',
  );
  $pane->cache = array();
  $pane->style = array(
    'settings' => NULL,
  );
  $pane->css = array();
  $pane->extras = array();
  $pane->position = 0;
  $display->content['new-1'] = $pane;
  $display->panels['left'][0] = 'new-1';
  $pane = new stdClass;
  $pane->pid = 'new-2';
  $pane->panel = 'right';
  $pane->type = 'node_body';
  $pane->subtype = 'node_body';
  $pane->shown = TRUE;
  $pane->access = array();
  $pane->configuration = array(
    'context' => 'argument_nid_1',
    'override_title' => 1,
    'override_title_text' => 'Bio',
  );
  $pane->cache = array();
  $pane->style = array(
    'settings' => NULL,
  );
  $pane->css = array();
  $pane->extras = array();
  $pane->position = 0;
  $display->content['new-2'] = $pane;
  $display->panels['right'][0] = 'new-2';
  $pane = new stdClass;
  $pane->pid = 'new-3';
  $pane->panel = 'top';
  $pane->type = 'node_title';
  $pane->subtype = 'node_title';
  $pane->shown = TRUE;
  $pane->access = array();
  $pane->configuration = array(
    'link' => 0,
    'context' => 'argument_nid_1',
    'override_title' => 0,
    'override_title_text' => '',
  );
  $pane->cache = array();
  $pane->style = array(
    'settings' => NULL,
    'style' => 'skinr',
  );
  $pane->css = array();
  $pane->extras = array();
  $pane->position = 0;
  $display->content['new-3'] = $pane;
  $display->panels['top'][0] = 'new-3';
  $pane = new stdClass;
  $pane->pid = 'new-4';
  $pane->panel = 'top';
  $pane->type = 'content_field';
  $pane->subtype = 'field_organization';
  $pane->shown = TRUE;
  $pane->access = array();
  $pane->configuration = array(
    'label' => 'normal',
    'formatter' => 'default',
    'context' => 'argument_nid_1',
    'override_title' => 0,
    'override_title_text' => '',
  );
  $pane->cache = array();
  $pane->style = array(
    'settings' => NULL,
    'style' => 'default',
  );
  $pane->css = array();
  $pane->extras = array();
  $pane->position = 1;
  $display->content['new-4'] = $pane;
  $display->panels['top'][1] = 'new-4';
$display->hide_title = PANELS_TITLE_NONE;
$display->title_pane = 'new-3';
$handler->conf['display'] = $display;
$page->default_handlers[$handler->name] = $handler;

Please if you need precisions, reply, I will answer.