I tested your code and it works fine (passing the 'images/2/config.xml' path to your loadjuicebox function) on clicking the link.
Here it is in action in a test gallery.

Make sure that your two 'config.xml' files are not identical.

Please post the URL to your web page so that I can take a look and help further.

Yes. Copy and paste everything between the <!--START JUICEBOX EMBED--> and <!--END JUICEBOX EMBED--> comments (including the <noscript></noscript> tags).

Without seeing your gallery and the configuration options that your gallery uses, I cannot determine the cause of your problem but it sounds like your images may not be filling the gallery's image area (resulting in a space between the bottom of the image and the thumbnails). Whether or not the images fill the gallery's image area will depend on the aspect ratio of your images, the aspect ratio of the gallery's image area (which, if your gallery's dimensions are expressed as percentages, will depend on the aspect ratio of the user's browser window) and the value of the imageScaleMode configuration option.
If you use the following configuration options in your gallery, the bottom of the main image will always be touching the top of the thumbnails (with no space in between) no matter what all the different aspect ratios are. (Try resizing your browser window with a gallery using these settings.)

thumbsPosition="BELOW_IMAGE"
maxThumbRows="1"
maxThumbColumns="10"
imagePadding="0"
thumbPadding="0"
imageScaleMode="FILL"

If you do not want to use imageScaleMode="FILL", then perhaps you could fix your gallery's dimensions (using absolute pixel values rather than percentages) so that the aspect ratio of the gallery's image area closely matches that of your images. In doing so, the aspect ratio of the user's browser window (always an unknown quantity) will no longer be a factor in the equation.

I was testing the coupon code by going through the motions to purchase the Single-Site license (which seems to work fine).
However, I see from your screenshot that you are trying to purchase the 5-Site license and I can confirm that this is currently not working (although the price is reduced on our own web page after entering the code).
Apologies for the confusion and for the code not working.
I have notified the team and this should hopefully be fixed soon but please be patient as there may be no-one around to sort the problem until after the weekend.

If you choose not to use WP-Juicebox, I would recommend using the baseURL method of embedding (documented here, as you are already doing). It allows you to upload your complete gallery folder (not just the contents) to anywhere you like on your web server. You would enter the embedding code into the body of the WordPress page (or post) ensuring that the method of entry is 'Text' rather than 'Visual'.

Your gallery currently displays the 'Config XML file not found.' message because your gallery uses the following code:

baseUrl : '/matt_blog/wp-content/JuiceboxGalleries/DaraghNessaWedding/',

... but the gallery does not seem to exist at that location.

You are seeing the 'Config XML file not found.' message only because WP-Juicebox is still activated in your WordPress installation and the web page is loading the 'juicebox.js' file from the plugin.
Your own gallery's embedding code contains the line:

<script src="/matt_blog/wp-content/JuiceboxGalleries/DaraghNessaWedding/jbcore/juicebox.js"></script>

... but there is no 'juicebox.js' file at that location either.

Make sure that you have uploaded your complete gallery folder to the correct location on your web server.

Also, if you choose not to use WP-Juicebox, you should deactivate it from the plugins menu as loading two different versions of the 'juicebox.js' file on the same web page (which may happen if you leave the plugin enabled and manually embed a Juicebox gallery of a different version) may cause problems.

When setting a watermark in JuiceboxBuilder-Pro, the watermark image becomes part of the main image itself (it is not simply superimposed on top of the image when the gallery is displayed) and cannot be removed.
However, when an image is purchased, Fotomoto will email you and request a high resolution version of the image be uploaded for printing. When this happens, you can provide a non-watermarked version of the image in question.
Please see this Fotomoto support page for details.

It sounds like your gallery may be affected by a known bug whereby captions can disappear under certain circumstances.
This bug should hopefully be fixed in the next version of Juicebox but, until then, it would be wise to avoid the following combinations of configuration options:

• captionPosition="BELOW_IMAGE" in conjunction with showImageOverlay="NEVER"

• captionPosition="BELOW_THUMBS" in conjunction with AutoPlay functionality

If this does not sound like the problem you are experiencing, please post the URL to your gallery so that I can take a look.

@maxphoto

The SEO content can be found in the gallery's 'index.html' file between the <noscript></noscript> tags (below the following comment):

<!-- Image gallery content for non-javascript devices -->

Make sure that you are using the latest version of JuiceboxBuilder-Pro (v1.3.2) and that you have selected the 'Add SEO Content' checkbox in the 'Customize -> Sharing' section.
If you need to upgrade your version of JuiceboxBuilder-Pro, please see the Upgrading Juicebox page for details.

Horizontal swiping within a gallery should change the main image. However, if your swipe gesture starts outside the gallery, it will likely scroll the whole page.

You could change imageClickMode from OPEN_URL to NAVIGATE or NONE.
If you still want to allow users to open the linkURLs associated with each image, you could set showOpenButton="TRUE" (to display the 'Open Image' button on the Button Bar) and use the languageList option to change its rollover text from 'Open Image in New Window' to something like 'Click to Open Web Page'.

Creating a new gallery (or updating the existing one) as and when you need to is fine but if you were to purchase Juicebox-Pro, you could still use my Flickr suggestion and have the images sorted automatically in your gallery using the flickrSort configuration option.

No. The 'juicebox.js' file is obfuscated and cannot be modified.

Here is a working example where the value of the cookie is actually the URL you would like the Back Button to open.

Paste the following code into a JavaScript file named 'cookie.js' and place it in your gallery folder:

function createCookie(name, value)
{
    document.cookie=name+"="+escape(value)+"; path=/";
}

function readCookie(name)
{
    var re=new RegExp("(?:^|;)\\s?"+name+"=(.*?)(?:;|$)", "i"), result=document.cookie.match(re), output=null;
    if (result!=null)
    {
        output=unescape(result[1]);
    }
    return output;
}

function eraseCookie(name)
{
    var d=new Date();
    document.cookie=name+"=; path=/; expires="+d.toUTCString();
}

Now use the following code as your gallery's 'index.html' file.

<!DOCTYPE html>
<html lang="en">
    <head>
        <title>Juicebox-Pro Gallery</title>
        <meta charset="utf-8" />
        <meta name="apple-mobile-web-app-capable" content="yes" />
        <script src="cookie.js"></script>
        <script>
            function backButton() {
                var value = readCookie('test');
                eraseCookie('test');
                document.location.href = value;
            }
        </script>
        <style type="text/css">
            body {
                margin: 0px;
            }
        </style>
    </head>
    <body>
        <!--START JUICEBOX EMBED-->
        <script src="jbcore/juicebox.js"></script>
        <script>
            new juicebox({
                containerId : 'juicebox-container'
            });
        </script>
        <div id="juicebox-container"></div>
        <!--END JUICEBOX EMBED-->
    </body>
</html>

Use the following code as your main page (which sets the cookie) and place it in your gallery folder:

<!DOCTYPE html>
<html lang="en">
    <head>
        <title>Back Button Cookie Test</title>
        <meta charset="utf-8" />
        <script src="cookie.js"></script>
    </head>
    <body>
        <div>
            <a href="index.html" onclick="javascript: createCookie('test', 'http://www.juicebox.net/'); return true;">Click here to open gallery and set cookie to open Juicebox home page.</a>
            <br />
            <a href="index.html" onclick="javascript: createCookie('test', 'http://www.simpleviewer.net/'); return true;">Click here to open gallery and set cookie to open SimpleViewer home page.</a>
        </div>
    </body>
</html>

Finally, set the following configuration options in your gallery's XML file:

backButtonUrl="javascript: backButton();"
backButtonPosition="TOP"

Try the following:

<div id="juicebox-container" style="margin: 0 auto;"></div>