You're welcome!
I hope you get on OK with your other galleries.
I'll mark this thread as [SOLVED] but if you run into any further problems, just create a new thread and I'll do my best to help you out.

Yes, your gallery at http://davebreen.com/jhbsocber20.html now displays correctly. If you do not see your gallery at this address, then please completely clear your browser's cache before reloading your gallery's web page to ensure that your browser is fetching the current files from your web server (and not using older, cached versions from your computer's hard drive).
(The gallery is working so if you do not see it, the issue if most likely a browser caching issue.)

PHP is a server-side scripting language. Some web pages may contain PHP code. The PHP code is processed on your web server before the web page is delivered to the user's browser. This allows for a dynamic (rather than just a static) website.
If any of your web pages use PHP, then you'll need to have PHP installed on your web server.
For example, WordPress is a PHP web application which requires PHP. It will not work without PHP.
Juicebox-Pro requires PHP for two functions, namely the Download Button and Password Protection. PHP 5.2 or later is required for these functions but, if you do not use them, then your Juicebox gallery will run quite happily without PHP being available.

When you visit any URL which does not exist on your web server, your web server defaults to displaying the "WordPress Coming Soon" page as your site's error 404 (file not found) page. You can change this error 404 page if you like but you'll need to find out where it is being set on your web server. (Your web host should be able to help you out with this.)

WordPress is a PHP web application which allows users to create a website or blog online in a web browser interface.
You do not need WordPress installed in order to have Juicebox galleries on your website.
However, if you do use WordPress, then there is a dedicated Juicebox plugin for WordPress (WP-Juicebox) which allows you to create and embed galleries into WordPress pages and posts from within the WordPress interface (without having to build your galleries on your computer with JuiceboxBuilder).
If you do not want to use WordPress for your website, then there is absolutely no need for it in order to have Juicebox galleries.

If you installed WordPress through your online hosting account's control panel, then there may be a way to uninstall it through the control panel, too. I'd investigate this first (ask your web host, they'll know) before you start manually deleting any files.

From what I've seen of your website and the changes you've made, I do not see any evidence of server-side caching but if you make any changes and don't see them immediately, then it's just something to bear in mind which might be causing the problem.

As I mentioned above, your http://davebreen.com/jhbsocber20.html gallery is now displaying and functioning fine and if you don't see it yourself, then please try clearing your browser's cache before reloading your gallery's web page.

I hope my notes above help to clarify a few things.
If you are having trouble with any other galleries, just post links to them and I'll try to help further.

As far as I can recall, the minimum Adobe AIR requirement for JuiceboxBuilder is AIR v2.0 or later so you should hopefully be able to download the last version of AIR for Linux (v2.6) from the Adobe AIR archive web page and install JuiceboxBuilder under this version of AIR.
Here's a direct link to Adobe AIR v2.6 for Linux (from the link above).
I hope this helps.

It looks like the folder name on your server is still 'JHBsocBer20'.
If you are changing all path references to lowercase, then you'll need to change this folder name to 'jhbsocber20', too
Everything else looks to be in place and I don't think you should be having any issues specifically because of Blue Host.
Hopefully, once you rename your gallery folder to lowercase, your gallery should display as expected.

Thank you for the links to your galleries.

I see that you are using a custom PHP file (named 'config.php')  to dynamically generate your gallery's XML data.
The problem lies somewhere within this file (which is not part of the Juicebox package).
There is something within this file that is not compatible with PHP 7.2 onwards.

Unfortunately, I do not have access to your 'config.php' file to inspect its code but opening it directly in a browser reveals the following warning:

Your use of the PHP count() function (whatever it may be) on line 10 is listed in the 'Backward incompatible changes' on the 'Migrating from PHP 7.1.x to PHP 7.2.x' support page here.

In order for your 'config.php' file to be compatible with PHP 7.2 onwards, you'll need to find a new PHP method to count whatever it is that you are counting.

I hope this points you in the right direction.
If you continue to experience difficulties, then please zip and upload your 'config.php' file somewhere (and provide a download link) so that I can inspect the code and hopefully help further.
Thank you.

Yes. Please see the following link for details: Using an External jbcore Folder

Essentially, you can upload a single instance of the 'jbcore' folder to anywhere you like on your web server and then load the 'juicebox.js' file from within this folder at the start of each gallery's embedding code. (Details are in the link above.)

This has the added advantage of allowing you to upgrade all your galleries at once (when new versions of Juicebox are released) by just replacing a single 'jbcore' folder.

You're welcome!

I don't know what is causing your problem but I do not think that it is a coincidence that the two images that do not display have the keyword "hidden" in their titles.
I have tried setting flickrShowTitle="FALSE" and flickrShowDescription="FALSE" to no avail.
I'd try actually changing the titles of these images to remove the word "hidden" (at least temporarily, for testing purposes) to see if this is, indeed, the cause of your problem.
If this does resolve your problem, then maybe you could use a term other than "hidden" (perhaps something like "secret" instead).

I'll try to figure out exactly what is causing this problem (whether it is a Flickr or Juicebox issue) to see if it can be resolved without changing your image titles.
I'll post back here once I've had a chance to investigate further.

Incidentally, I've just created a test Juicebox gallery using local images with the word "hidden" in their titles and captions and the gallery displays all images so, at the moment, it does not look like a Juicebox issue (at least not with local images).

I've also just added the word "hidden" to one of my own Flickr images (in the title and description) and a new Juicebox test gallery displays this image without any problem.

Very strange...
I'd certainly try removing all instances of "hidden" from your own images and, failing that, try reuploading them to Flick (as additional images and/or replacing the current images) to see if this helps.

I'll take another look at this later on when I have more time.
I hope you get on OK in the meantime. Please keep me posted with any updates on your troubleshooting. Thank you.

I understand your concerns (I truly have the same concerns) but, unfortunately, I have no more insight into the future of AIR than you do and, at this moment in time, I genuinely have no news on the future of JuiceboxBuilder.
All I know is that Juicebox itself is still alive and that work has started on the next version (which will likely be a bugfix release).
I really do not know any more than that. I'm sure that the developers are aware of the AIR issues and all we can do, myself included, is hope that JuiceboxBuilder can live on in some form or other beyond the Harman procurement of AIR.
I wish I had more information (good or bad) to give you but I'm as much in the dark as you are just now.

It should be noted that there are alternative ways of creating Juicebox galleries that do not rely on JuiceboxBuilder and AIR. I realise that these methods may not be suitable for all users (and it is certainly a less than ideal scenario) but the Lightroom plugin at least provides Lightroom users with a longer-term solution (with the Pro version of the plugin featuring full control over all Pro configuration options just like JuiceboxBuilder-Pro).

I'm sorry that I do not have any more information at this time but I'll be sure to post back here if I hear anything relevant to this matter.
Thank you for your concern and continued support of Juicebox.

If you were using Juicebox-Lite, then it could have been due to a WP-Juicebox upgrade.
WP-Juicebox comes bundled with Juicebox-Lite and if you upgrade WP-Juicebox, your Pro 'jbcore' folder will be overwritten with the Lite version.
Reinstating your Pro files is a simple task of uploading your Pro 'jbcore' folder (from your Juicebox-Pro zip file) to your 'wp-juicebox' directory (which should take less than a minute of your time). (You could also just remove the Lite 'jbcore' folder from the WP-Juicebox package before upgrading to prevent your Pro 'jbcore' folder from being overwritten.)

The screenshot of your gallery does seem to conform to the screenshot of your gallery settings window. (The screenshot of your gallery windows shows maxThumbRows="1" and maxThumbColumns="6" and this is displayed in the screenshot of your gallery.)

Setting maxThumbRows="6" and maxThumbColumns="1" will definitely make a difference.

If it does not seem to make a difference for yourself, then the problem is almost certainly a caching issue.
After making changes on an 'Edit Gallery' page, make sure that you click the 'Save' button at the bottom of the page and if you do not see the changes you expect to see, make sure that you are 100% certain that you have completely cleared your browser's cache before reloading your gallery's web page. (Sometimes refreshing the page with F5 or even Ctrl+F5 is not enough.)

I've just double-checked all this by creating a sample gallery in WP-Juicebox v1.5.1.2 (using Juicebox-Pro v1.5.1) using maxThumbRows="6", maxThumbColumns="1" and thumbsPosition="LEFT". The gallery displayed as expected. I then edited the gallery (on the 'Manage Galleries' page and swapped the '1' and the '6'. Again, the gallery displayed as expected (with the rows and columns swapped).

If clearing your browser's cache does not help, then maybe the issue is with server-side caching. Your web host could perhaps have server-side caching enabled on your hosting account and, even though files have changed, your web server could still be serving older versions of these files for a certain period of time.
Please check in with your web host and ask if they have server-side caching enabled on your hosting account and, if so, ask if they would be willing to remove it.
Caching can certainly be useful but it can also sometimes be a hindrance to development.

If you click on the attachment link, the image will be displayed. Below the image, you'll see a download link. Each time the image is downloaded via this link, the download counter is incremented by one. (Most people will be content with viewing the image in place and will not download it.)

WP-Juicebox has individual interface controls for Lite options only.
Pro options must be entered in the 'Pro Options' text area of the gallery settings window, one per line, such as:

expandInNewPage="TRUE"
showImageOverlay="ALWAYS"

This has always been the case with WP-Juicebox (and setting Pro Options in a WP-Juicebox gallery is noted in the WP-Juicebox support page here).

You will find the 'Pro Options' text area in the gallery settings window when you first create a gallery.
You can access the gallery settings window for a pre-existing gallery by going to 'WP-Juicebox -> Manage Galleries' (from the WordPress Dashboard side menu) and clicking 'Edit' next to the gallery that you'd like to modify.

Try adding something like the following to a gallery's 'Pro Options' text area, changing the values as necessary:

thumbWidth="75"
thumbHeight="75"
thumbsPosition="LEFT"
maxThumbRows="10"
maxThumbColumbs="3"

The text in the top-left is the gallery title. To remove the gallery title, set  the following in the gallery's 'Pro Options' text area:

galleryTitlePosition="NONE"

The text near the bottom of the image is the caption area.
By default, WP-Juicebox uses the image filename (without the extension) as the image title. ("b-forgiving-1" in your screenshot.)
You can remove this by deselecting the 'Display Image Titles' checkbox (just above the 'Pro Options' text area).
You can remove the image number ("6/6" in your screenshot) by setting the following in the 'Pro Options' text area:

showImageNumber="FALSE"

You can remove the entire caption area (without needing to remove the image title and image number separately) by setting the following in the 'Pro Options' text area:

captionPosition="NONE"

For reference, a list of all Pro Options can be found here.

I hope this helps.

The 'Home' icon is the Back Button, displayed when backButtonPosition is set to either TOP or OVERLAY (and backButtonUseIcon is set to TRUE).

You can have the Back Button redirect to any web page you like by setting backButtonUrl (in JuiceboxBuilder-Pro's 'Customize -> Back Button' section).
The value for backButtonURL can be a relative path (relative to the web page containing the gallery's embedding code) or an absolute path (starting with either http:// or https://), for example:

backButtonUrl="http://www.example.com/index.html"

For reference, a list of all Back Button options can be found here.

I hope this helps.