Error when previewing PDF page in Drupal Views

Hi,

I am working with version 6.x-1.1 of the Views PDF module together with Drupal Views 6.x-3.0.

I have specified a PDF display in a view. When I try to preview it, I get the following error message.

Any clue on how to fix it?

An error occurred at //index.php?q=nl/admin/build/views/ajax/preview/get_approval_steps.

Error Description: 
Fatal error: Call to a member function get_preview_info() on a non-object in /sites/all/modules/views/includes/admin.inc on line 428
Call Stack:
0.0002     665664   1. {main}() /var/www/drupal/index.php:0
0.2334   52118864   2. menu_execute_active_handler() /var/www/drupal/index.php:17
0.2407   54003728   3. call_user_func_array() /var/www/drupal/includes/menu.inc:350
0.2407   54004344   4. views_ui_preview() /var/www/drupal/includes/menu.inc:350

Thanks