I have a zenphoto installation in a sub folder which seems sometimes to try to return to the wrong page and results in a 404

The zephoto is installed in a folder inside the public_html folder so to reach it the url is:
https://main-domain-name/zenphoto-folder-name/

So I am considering using this part of the configuration file:

// define('WEBPATH', '/zenphoto');
// define('SERVERPATH', '/full/server/path/to/zenphoto');

but am doubtful as to what exactly to put in these paths

is the WEBPATH simply the name of the folder in which the zenphoto installation resides?
is the SERVERPATH (CPanel installation)
/home/domain-name/public_html/zenphoto-installation-folder/
or
/home/domain-name/zenphoto-installation-folder/

Thank you for all the help you provide,
Richard

The webpath is the folder within the root of the domain zp is installed in (this is the same for subdomains which are independent domains). So on your example https://main-domain-name/zenphoto-folder-name/ that would be /zenphoto-folder-name

The serverpath is the full path on the server filesystem. What exactly depends on the server. Perhaps your host or consult the host docs/backend if unsure.

If each domain as its own folder and a public_html subfolder within this would be probably indeed the server path
/home/domain-name/public_html/zenphoto-installation-folder/

Most hosts I know have a sort of public_html which contains the domain folders. Our hosts for example does setup those but we can freely define/rename/structure that.

Do you have modrewrite enabled and is the htaccess file correct? There is an entry for a rewrite base which is the same as the webpath.

Thank you - I will check out your various suggestions.
Richard