Nivo Slider on Apple Products images not loading

[RodrigoCarreira]

Hello everyone! I've been using Xara Web Designer 10 to build this website
http://www.mapandapp.com
Everything has been pretty smooth, but I've hit a snag when it comes to Apple products, has it seems my Nivo Sliders work perfectly on everything else (desktop, android smartphones and tablets) but not on Iphones, Ipads or Ipods..
What's very confusing, is that the error seems to occur randomly, as in one login session I can see a slider on a page not working on an Iphone, but if I use an Ipad on the same page it loads up..
Any ideas?

[RodrigoCarreira]

Bump, 88 views and no replies, i'm guessing this is a bit more complicated than what I was hoping it to be? :/

[Egg Bramhill]

Viewed your site and can't see a NivoSlider. Where is it?

[bb2]

HI i can see the slider at http://www.mapandapp.com/directory.htm and checked it on the ipad mini and ipad and its displaying correctly. i refreshed the page several times and couldnt cause it not to display

[ss-kalm]

Click on the "directory" link (http://www.mapandapp.com/directory.htm) at the top Egg.

Beat me to it , should have refreshed the page, prior to posting

[RodrigoCarreira]

Sorry guys, forgot to mention that the homepage didn't actually contain one of them, the problem is the website is becoming pretty big with over 1000 pages and growing everyday.
My main issue, is not beeing able to pinpoint exactly what's the cause of this issue, as on the same device, it'll load up fine today, and keep loading forever without actually displaying anything, tomorrow.
Nobody seems to have a problem with it except my boss lol.
Anybody got any idea as to why a slider would load up fine on a specific page, and 2 hours later, same device same page same internet connection, and it doesn't load?