http://iosscripts.com/iosslider-vertical is a 404.
It is unclear from the documentation if iosSlider is required to be loaded in unison with iosSlider-vertical or not.
Under "Include The Necessary Javascript Files", you have "The jQuery library and iosSlider Plugin scripts must be included in the HTML header of the web page. The jQuery library must be included first for the iosSlider plugin to function." but in the example below that, you're loading the vertical version.
In the "Add The Javascript" section, you have two separate function calls to initialize iosSlider-vertical:
$('.iosslider-vertical').iosslider-vertical();
$('.iosslider-vertical').iosSliderVertical({ ...
This difference is littered throughout the rest of the documentation. Was this the result of a refactor?