When using jQuery Update (https://drupal.org/project/jquery_update) and version 1.8 of jQuery, the slideshow height is not set and therefore the slideshow is not seen because of the absolute positioning of the slides.

This issue was brought up here, but was never addressed: #1786636: Image loader script not working with jQuery 1.8

This probably isn't urgent at this point as I would guess that not too many are using jQuery 1.8 yet, but it will likely be an issue if that version ever becomes used more often.