Some views not working for registered users

I´m using:

Views 7.x.3.3
Views Slideshow 7.x.3.0
Drupal 7.12

Theme: AT Commerce 7.x-2.0-rc3

The site I developed works perfect on my local environment.
Once uploaded to the public host it also works OK for unregistered users.
If I log as a registered user or even administrator the pages that contains a view of "product display" nodes don´t work, showing only an unformatted listing of the menu links and nothing more.

I find confusing that all works fine for UNREGISTERED USERS on the external hosting as in the local one, which means that alll necessary components are installed. Once I login with any user no matter the privileges the pages with the involved view don´t work anymore. I´m attaching screen capture images for registered and unregistered users.

Also if I try to modify the view as an administrator I recieve an AJAX Error 500 Internal Server Error. ALL OTHER VIEWS WORK OK.

I really appreciate any help on this issue.