I'm not sure why this might be happening. I've not seen it happen before and, as far as I can remember, no one else has reported such an issue.
... about 50 or so new 'Gallery" folders were created...
... 93 folders called "Gallery" had been made.
It sounds like, whatever the problem is, it doubles the number of duplicate folders on each iteration.
How are the duplicate folders named? This might give us a clue as to how they are being created.
For example, if you have a gallery page named 'gallery', are the duplicated folders on your server named 'gallery-2', 'gallery-3', etc. or do they use a different format such as 'gallery (2)', 'gallery (3)', etc.?
Take a look at your showkase/_data/pagesdata.txt file in a plain text editor. I expect you might find all the duplicate folders listed in here.
If so, and your Showkase site is self-contained in its own folder (with no non-Showkase content in the Showkase root directory), then the following might work.
(1) If you are not already using the latest version of Showkase (v1.6.1), please upgrade following the Upgrading Showkase instructions.
(2) Manually delete any duplicate folders on your server that you know are not part of your actual Showkase site.
(3) Run 'System -> Repairs -> Repair' to rebuild the page records.
If this does not work, here are a few other things to try.
Try installing a fresh Showkase site into a new subdirectory on your server to see if the same thing happens with this new site. As long as you install the new site into a folder of its own, it should not interfere with your existing site and it will be self contained (so it can easily be deleted after testing if necessary).
If duplicate folders are created within the new site, then this would suggest that the problem is somehow related to your web server or its settings (although I would really need access to both your server and existing Showkase site in order to try to determine the cause of the problem).
If the new site seems to function OK without creating duplicate folders, then you could perhaps use this site as your main site and import the pages from your original site (via Showkase's 'Site -> Import' functionality) to avoid the need to recreate them from scratch.
You could then move the new site into the location of the original site (deleting the original site first) by following the Changing Your Installation Directory instructions.
Hopefully the suggestions above will help.
Important note:
Please take a full backup of your existing site before trying any of the above, just in case anything goes wrong and you need to reinstate your original files at a later date.