After adding a folder to a static slideshow (using all defaults), upon clicking the OK button in the user interface I get:
While executing onclick in dmxHTML5Slideshow.htm, the following Javascript errors occurred:
At line 2788 of file "...HTML5 Slideshow:jQueryLib:jQueryComponent_lib.js": sURL has no properties

Hello Michael Hogan.

Can you please try to clear your DW cache file?
You can understand how to do it in the following article:
Clearing Dreamweaver's cache

Regards: V.Vulev