Nextgen problem to show the gallery

HI all, I’m sorry for my not perfect english: is not my primary language!
I need an help: I managed many website for me and friends and I always used NextGen Gallery plugin without any problems.
Now I’m using Nextgen plugin (2.1.15 version) on WP (4.2.5 version) with Atahualpa theme (3.7.24 version) and I have a big problem: I put the gallery with Basic Thumbnails on a post but, in the webpage, when I click on any thumbnails the page doesn’t show the normal gallery but only the single picture that I clicked.
I’m not able to understand why it happens?????

Anybody can help me???

Thank in advance!