Themes conflict: WP-Explotion by Zerge from themeforest
https://themeforest.net/user/ZERGE
made a report here
https://www.nurikidy.com/2013/08/02/problem-with-nextgen-gallery-v2-0/
today try the 2.0.7, and problems still remain as reported on blog post above
but it seems the only themes that working normal with NextGen 2.0.x in my case is only WP Twenty Twelve ??
