Seems the community maintains a forum at /r/overflowingbra.
Going from what I can see there, and the error messages, I'd say the software on their server was not kept up to date and got exploited, and they either haven't cleaned up the mess, or they updated PHP and the like, and it broke what they were using, like Gallery.
The Gallery project hasn't been maintained for the past four years, it's not safe to use, there are probably bugs and exploits that will not be fixed.
Source: one of the former devs, and see here http://galleryproject.org
You might consider Gallery Project. I haven't used it in quite a few years and didn't particularly like it at the time but it may work for you or at least be worth a look.
I was all set to come in and suggest Gallery, but it seems they ceased maintaining it back in 2014. Even so, the last time I used it (probably 2013-ish), it was quite nice / reliable. It's at least worth a look. :)
You have to login as Admin, select an album, click more (at the top), edit album properties, change type to private album.
Setting a user to allow them to manage albums doesn't provide them the ability to change the album to private.
Photo Station needs some work. Gallery (http://galleryproject.org) is so much more advanced than Photo station.
You can look at the various gallery scripts and see if one matches your needs. I believe your requirements are going to force at the least a customized version of one of those types of scripts if not a bespoke solution.
gallery has tag support plus plugins available : http://galleryproject.org/
http://phpalbum.net/ - has auth and says it imports keywords
I don't know if either of those has views associated with tags/keywords but odds are you can write the code or hire it out.