[Plugin: NextGEN Gallery] Slideshow navigation bar half hiden

Hi everyone,
the slideshow I am using is not working as well…
You can see an example here : http://www.thekoalan.com/gp/fr/electromenager/
The navigation bar is mostly hiden and I think the images are shifted because the loading icon is not centered.

Did you ever had this problem ? Does someone know how to solve it ?
Thanks for you answers.