This script works by walking the slideshow backwards. It seems that sometimes the slideshow isn't continuous, perhaps because entries have been deleted. I've set the script to skip the ones I know to be missing, but if more missing ones show up, the script will stop partway through. The data should be right for the part of the slideshow that got walked, but entries newer than the missing one won't be counted. If the output starts with "Run completed", it made it all the way to the first entry. If it says "Run stopped", it didn't. I'll look into that, if it happens.
Questions? Comments? aneel at loath.org