If your slideshow only shows the first image, you should check the Image Folder setting for the module: if the folder has a trailing slash (i.e. “images/stories/slideshow/”) you should cut it (i.e. “images/stories/slideshow”) and voilà 🙂
The Helio demo on JA website *does* have this flaw: http://www.joomlart.com/demo/#templates.joomlart.com/ja_helio 😉
And you get the same error if you install the template using the quickstart archive.
Bonus: while looking at the cause of this error I found a typo in the mod_jaslideshow.php source file: at line 182,
echo '<script src="'.JURI::base().'/modules/mod_jaslideshow/...
should be (look at the slashes)
echo '<script src="'.JURI::base().'modules/mod_jaslideshow/...
Seems there are some slash-oriented flaws in this module, arent there? 😉