I recently installed the Simple Image Gallery on my Joomla site and it works fine for all my image galleries except one. Here is the code that appears in article editor:

I inserted an image link with the following source: images/photo-gallery/2010/HPIM6259.JPG. There is only one image in the folder.

Here is the 2nd piece of code: {gallery}photo-gallery/2010{/gallery}.

This is a link to the screenshot of the error message I receive when I open the page (which only displays the image from the link code above).
i.imgur.com/BsS5Q3e.png?1

Hello Keith,

Try using a different image to see if the issues lies with that specific image.

I tried opening this gallery originally with over 100 images. That's when I first saw this error, which prompted me to try to isolate the problem. I then moved most of the images out of the folder, leaving only 5 images. I saw the same error trying to open the folder so I moved all those images, except one, out of the folder and I still get this message. I'm completely stumped.

Please open a ticket at the helpdesk.
In the ticket do not forget to include a link to the issue and administrator credentials,

It seems that I'm unable to open a ticket because I get this message: "You cannot add a ticket because you do not have any active subscriptions." What does that mean?

It means that you need an active subscription (your current subscription has expired) in order to open a ticket.