I resolved it. I just could not login in wp login after I installated this plugin.
So through ftp I deleted nextgen plugin and changed plugins folder and renamed it plugins-deactivated. So I just enter in backend panel and renamed plugins-deactivated in its original name. I just activated again all plugins and my website run again.
I think that before to release an update it should be very important very important to consider any bugs. Otherwise it’s a problem for all people using this new nextgen plugin version.
