Since upgrading to Zenphoto 1.5 my debug log is being flooded with the following message:

{3862365:Wed, 27 Jun 2018 04:53:27 GMT}
NOTICE: Use of undefined constant _GALLERYINDEX - assumed '_GALLERYINDEX' in /home/bpskdk/public_html/zenphoto/zp-core/rewrite.php(100) : eval()'d code on line 1
eval called from rewriteHandler (rewrite.php [100])
from include (index.php [38])
from index.php [31]

My setup is as follows:

Zenphoto version 1.5 (Official build)   
Current locale setting: en_US.UTF8  
PHP version: 5.6.36
MySQLi version: 5.5.5

Look in your /zp-data/zenphoto.cfg.php file.
You will see something like this around line 72:

$conf['special_pages'] = array(

    'page'=>            array('define'=>'_PAGE_',   'rewrite'=>'page'),

    'search'=>          array('define'=>'_SEARCH_', 'rewrite'=>'_PAGE_/search'),

    'archive'=>         array('define'=>'_ARCHIVE_',    'rewrite'=>'_PAGE_/archive'),

    'tags'=>            array('define'=>'_TAGS_',   'rewrite'=>'_SEARCH_/tags')

);

You have to add one line so it looks like this:

$conf['special_pages'] = array(

    'page'=>            array('define'=>'_PAGE_',   'rewrite'=>'page'),

    'search'=>          array('define'=>'_SEARCH_', 'rewrite'=>'_PAGE_/search'),

    'archive'=>         array('define'=>'_ARCHIVE_',    'rewrite'=>'_PAGE_/archive'),

    'tags'=>            array('define'=>'_TAGS_',   'rewrite'=>'_SEARCH_/tags'),

    'gallery'=>         array('define'=>'_GALLERY_INDEX_',  'rewrite'=>'_PAGE_/gallery')

);

in 1.5, this line already exists !
see https://github.com/zenphoto/zenphoto/blob/master/zp-core/zenphoto_cfg.txt

Yes, but when you just upgrade the line is not added.
At least, not on my local installs.

That's sounds like a bug then sadly…

My sincere apologies for not replying sooner.

The update to the /zp-data/zenphoto.cfg.php file fixed the problem for me.

Many thanks.

Thanks for the follow up. We'll also see to fix this for the next bugfix update.