Try uninstalling JuiceboxBuilder-Pro, searching your hard drive for any and all instances of 'JuiceboxBuilder-Pro' and manually deleting everything found. Then empty your trash and reinstall the application.
If this helps and your search returned any entries, it might help other users who encounter the same problem if you could post them here (so that the other users know what to delete).

If this does not help, then it might help if I could try opening your gallery with JuiceboxBuilder-Pro myself, just to make sure that there is nothing wrong with the gallery itself. Perhaps you could zip and upload the gallery folder somewhere and provide a download link. Thank you.

The XML data has to be in its own separate file (it is not possible to simply pass a string of data to the configURL configuration option in the embedding code).
Also, the file containing the XML data has to be fully formed before Juicebox loads it.
This could be achieved with a server-side scripting language, such as PHP (which would create the XML file on the server before Juicebox loads it), but not with client-side JavaScript.

An example of how this can be achieved can be found in the answer to Query #3 in this forum post.

You could pull in data from whatever source you like and, instead of simply echoing the output, you could build an XML file using PHP DOM techniques.

Your gallery seems to be working OK just now. Your images display OK when I view your gallery myself.
Perhaps there was a temporary glitch with either Flickr itself or your internet connection which has now been rectified.

Edit:
I'm glad it seems to be working OK at your end now, too. Thank you for posting back to let me know.

Unfortunately, it is not possible to enter code such as backButtonText="<a><img src='jbcore/classic/img/Logo-Dark.png' /></a>" into the Pro Options text area in the Juicebox plugin for Lightroom as the text is split into key/value pairs using the = character and the second = character in your backButtonText line breaks the parsing of the Pro Options.

Either:
(1) After creating your gallery, open the gallery's 'config.xml' file in a plain text editor and enter the backButtonText configuration option as an attribute to the opening <juiceboxgallery> tab.
... or:
(2) Open and edit the gallery with JuiceboxBuilder-Pro. You could perhaps create your own custom preset in order to quickly apply a certain collection of settings to existing galleries. Please see the Presets section of the JuiceboxBuilder User Guide.

You can certainly load and parse an XML document (such as a gallery's 'config.xml' file) using AJAX. An example can be found here.

I'm not sure exactly what you are trying to do (perhaps you could explain in greater detail), but the likelihood is that it is possible with both Juicebox-Lite and Juicebox-Pro.

I hope the link above helps point you in the right direction.

I'm glad that you have got your links working but, just for the record, in my own tests, the slash is required for Safari 5.1.7 on PC (although Safari on PC is more than a little outdated now, the last update being over two years).

The following formats should work in all browsers:

linkURL="http://www.example.com/gallery/#2"
linkURL="http://www.example.com/gallery/index.html#2"

As long as the 'wp-juicebox' folder is in your WordPress 'plugins' directory (and the 'wp-juicebox.php' file is inside the 'wp-juicebox' folder), then the plugin should be listed on your Dashboard -> Plugins page.
Please double-check that the 'wp-juicebox' folder is in the correct location on your web server.

The theme you use should have no bearing on whether or not a plugin shows up in the list but, being that you are experiencing difficulties, you could try temporarily reverting to the default WordPress theme to see if this makes a difference.

I would be happy to offer more help but in order to investigate further, I would need to see the problem for myself which would require access to your WordPress installation and your web server.
If you are agreeable to this, then please email me the URL and login details to your WordPress installation and the FTP login details to your web server and I will take a look and try to figure out why the plugin is not showing up.

In the meantime, if you like, you can manually embed Juicebox galleries into your WordPress pages or posts using the baseUrl method of embedding as documented here.
Essentially, you would create a Juicebox-Pro gallery using JuiceboxBuilder-Pro, upload your entire Juicebox gallery folder (not just the contents) to your web server and then paste the baseUrl embedding code into the body of your WordPress page or post (ensuring that the method of entry is 'Text' rather than 'Visual').
It does not matter where on your web server you upload your gallery folder to as long as the two paths in the embedding code (the path to the 'juicebox.js' file and the baseUrl itself) are correct.

No. Juicebox-Lite and Juicebox-Pro galleries both display on Android devices equally well. (Likewise with SimpleViewer-Standard and SimpleViewer-Pro.) There is no distinction between embedding a Lite/Standard (free) version and embedding a Pro version .

A blank screen on a mobile device usually implies one of two things:
(1) JavaScript is disabled in your browser.
... or:
(2) You are using a 3G connection (rather than wi-fi) to view your gallery.

This suggests that the problem is not (1) above.
If you are trying to view your gallery over a 3G connection, then please see this FAQ which contains a solution to the problem.
Why can't I view my gallery on a 3G mobile connection?

You should be able to add Pro configuration options manually by specifying the settings in optionName = "optionValue" format within the advanced module settings ('Pro / Manual Configuration Options').
Please note that we did not write the Juicebox module for Drupal ourselves and support for the module would be better directed towards the Drupal forum where the author of the module should be able to help you further.

Try one of the two following suggestions:

(1) Use an opaque (rather than transparent) expandedBackgroundColor (in JuiceboxBuilder-Pro's 'Customize -> Color' section). For example, try setting expandedBackgroundColor="rgba(255,255,255,1)" (make sure that the 'Opacity' value is set to '1'). This should ensure that no elements from your web page are visible when the gallery is expanded.
... or:
(2) Set expandInNewPage="TRUE" (in JuiceboxBuilder-Pro's 'Customize -> General' section). When the gallery is expanded from the Splash Page, it will be displayed on a page of its own rather than on top of the embedding page.

Hopefully one (or both) of these suggestions will be a suitable solution to your problem.

It is not possible to have the shared image's thumbnail displayed in the pop-up share window due to limitations imposed by Facebook on what data can be passed via their share URL. Only one thumbnail can be used per web page. (The link will still point towards the correct image within your gallery, though.)

The image used in the Facebook sharing pop-up window can be set using an Open Graph og:image <meta> tag in the <head> section of your web page, such as the following:

<meta property="og:image" content="http://www.example.com/images/thumbnail.jpg" />

If you create a gallery with JuiceboxBuilder-Pro, an og:image tag will be automatically generated and included in the gallery's 'index.html' file. If you are embedding your gallery in an existing web page alongside other content, then you will need to add an og:image tag manually.