Sliders are a problem!

Although I was enthusiastic of the theme when I purchased it and I still find it fantastic, I’m having lots of trouble with the sliders. All of them! I made no change to original theme’s file but still I can’t understand what’s wrong ! On ThemeForest site the demo was ok but not on my site.
In order:
– EASY SLIDER: is the only one that works UNTIL the 2nd slide. Starting from 3rd slide nothing happens independently if you loaded 4,5,6 …images, besides, even if the autorotation is set as active, it remains on the 2nd slide and does not change even if you click on right/left arrows or on small round navigation buttons !
– FULLWIDTH SLIDER: this is even worse as doesn’t work at all! no images, no autorotation, no manual click back and forth! for the image I can only see a question mark and that’s all !
– ADVANCED LAYERSLIDER: same as the FULLWIDTH SLIDER
It’s about 2 weeks I’m running around this matter and watched lots of tutorials, read posts and looked for any useful hint to solve this issue but… now I feel really very frustrated as I can’t come out of this and I need to!
So I wonder also if instead of the above SLIDER solutions I could use another one that might work and giving not problems.
I’m aware the support is given on a voluntary basis and I can’t expect any ‘miracle’ but still hope for a solution!
I’m working on Enfold v.1.3.1 using the Dummy theme and already created the site structure (pages, menu ecc) and not wishing to restart the done work by installing an update that overwrites my previous work, I want and need to avoid it !!!
Thank you for your attention and, hopefully, help to solve this issue and to continue spreading the enthusiasm on this fantastic WP theme… if I can come out of this :)
Nona