I had errors on an old installation of zenphoto. I created a new installation with the latest version and a new database. I wish to export or copy the old database into the new one. I tried copying using PHP MyAdmin, but I get errors. Is there a way to do this? I also thought of just exporting the images and then re-uploading them manually, but I don't know how to do that. Any help welcome!

You cannot import data from an old version to the latest. You didn't say which version the old one was but over the years things changed in the database.

You should install the old version first, import there the old data and then update to the lastest.

Here is some info about moving installations (which basically is what you are trying to do):
http://www.zenphoto.org/news/moving-and-changing-existing-installations/#moving-on-the-same-server

If you were on an very old version you may not have the database backup plugin. In that case phpmyadmin should work too. But note the order of things to do noted on the page referenced.

Unfortunately, I don't even know what version the old ZP was - many years ago. And the old installation wasn't working anyway, I had no access to the admin at all. That's why I installed the new ZP. So, ok - I won't be able to import data from old version. Is there a way to EXTRACT the content of the database back into JPG and text files?? I can then at least re-upload into the new ZP. (Tedious, but that's life sometimes). Thanks.

If your old installation is still intact I would simply try to upgrade to the latest version.
http://www.zenphoto.org/news/installation-and-upgrading/#upgrading

Is there a way to EXTRACT the content of the database back into JPG and text files??

Use FTP to access your server and download everything in the [i]albums[/i] folder.

Is there a way to EXTRACT the content of the database back into JPG and text files??

No, there is no way to get the database contents of the old install back if you don't know the version anymore. The database backup would have been a way but then the versions would have had to match.

As fretzl suggested since the gallery/albums of Zenphoot is filesystem based you can simple re-upload the folders from the old install's `albums` folder to the one of the new install. Zenphoto will recognize those.

But that will NOT include the database contents in case you had entered titles, descriptions etc. manually. It will only take EXIF/IPTC data embeded in the images itself though.