Thanks Steven.  Clearing the cache worked and I was able to have all the thumbnails come up.  I have been having problems with internet connection dropouts.  The line has been check and is ok and now I have changed the modem as I think this is the most likely culprit.  So far so good.  Thanks for your prompt attention.  I will be upgrading to Pro as a result of your quality service.

Thanks for your prompt response.

Please check that the images have been uploaded to the correct location on your web server
       I've done this and they are.

check that the thumbURL paths in the gallery's XML file point towards the thumbnail images correctly.
       I don't know what this is or how to do it.

You might like to try re-uploading the thumbnail images to your web server in case something happened during the initial upload resulting in missing or corrupt files.
       I have done this several times.  I have deleted and recreated my collections in LR5 twice and have redone the gallery at least 5      times, and still the same results.  I even created and posted another gallery using the same template and it worked properly.  For some reason it has only happened with this particular group of pictures.

Please also see this FAQ:
My images show locally, but not when I upload them to my website. Why?

       I have checked the extensions, the number of items in the files and the sizes and they all match.  I have not gotten any error messages in my uploads or anywhere in the process.

Also, check the permissions of the thumbnail files (with a dedicated FTP program such as Filezilla or within your web hosting account's online CPanel) and their parent folders to make sure that they are not too restrictive. Default permissions of 644 for files and 755 for folders should be fine.
       The folder permission are the same as the all the other gallery folders, but I don't understand or know how to do the rest of what is listed here.  Remember my site is done on iWeb and the galleries through the LR5 plugin.  I don't do any type of coding.  When I create the gallery I export that file to my HD and then use Cyberduck to move the file to the website server.  This is a drag and drop process. I have 50 galleries loaded on my website done with this process.

This is the URL for the gallery:  http://jwolfphotog.macmate.me/jkpwolf/g … index.html

I wanted to try Jukebox as all my galleries were Flash and they could not be seen on mobile devices.  I have converted 7 but this is the only one presenting a problem.  If this solution works I would probably upgrade to pro.

I am using the lite version as a LR5 plugin.  I am removing my old Flash galleries and redoing them with Juicebox.  I have already done 5 galleries without a problem.  On the 6th, some of the thumbnails on the website are blacked out.  This is only on the first two strips.  All the pictures are there and show properly, it is only the thumbnail.  In LR5 everything looks normal.  All the thumbnails are there.  I have restarted LR a couple of times.  I have deleted and redone the Juicebox gallery several times.  I even have 2 templates that I use and the same thumbnails are missing every time.  My website is done through iWeb and I use Cyberduck.