I get the following error on my view where I want to have the Excel export icon.

Notice: Undefined property: view::$feed_icon in views_export_xls_plugin_style_xls->attach_to() (rule 43 of E:\Users\Mathijs Groothuis\Mijn websites\NSG-Drupal\sites\all\modules\views_export_xls\views\views_export_xls_plugin_style_xls.inc).

I already reinstalled the module, but still an error.

After I looked more closely on rule 43 in file views_export_xls_plugin_style_xls.inc I saw:

function attach_to($display_id, $path, $title) {

    $url_options = array('html' => TRUE);
    $input = $this->view->get_exposed_input();
    if ($input) {
      $url_options['query'] = $input;
    }
    $variables = array(
      'path' => $this->feed_image,
      'alt' => 'Icon for xls export',
      'title' => 'Export to xls',
      );
    $image = theme('image', $variables);
    $this->view->feed_icon .= l($image, $this->view->get_url(NULL, $path), $url_options);
  }

When I remove the dot in this rule:

$this->view->feed_icon .= l($image, $this->view->get_url(NULL, $path), $url_options);

It is working again. Is there a reason for the dot to be there?