@nymills i downloaded a database backup, and saw that indeed, because the site was set up and tested in a different location first, some entries in the database referred to the old location. I edited those entries to point to the new location (deleted the old database and uploaded the edited version) and then also used the FAQ instructions to change the settings.
It is a bit complicated but thankfully it worked for me 🙂
Update: I managed to fix this using the FAQ http://www.nextgen-gallery.com/galleries-opening-lightbox/
In the end i even had to manually edit the database but it works again 🙂
same here sadly. I am using nextgen on aabc.nl and since updating it to the latest version lightbox no longer works.
– I submitted a bug report. Any ideas on quick fixes in the meantime?