I came across this post from last year: http://wordpress.org/support/topic/plugin-promotion-slider-categories-not-working-with-version-320-and-321?replies=7 and it describes the problem I'm having. Promotion slider works when I don not define a Category, but as soon as I define two categories it does not work. Not sure what info to provide you. The website link is http://www.franklinschool.jcwstaging2.com/admissions/.
If you need more info let me knoe what you need and I'll try and provide it.
I do like the plugin, BTW.