I've solved my own problem!
It would appear with the latest version of the
store hack, all the lottery stuff is already in the storeadmin.php file, so in the instructions for the
lottery hack, ignore the additions they say to make to storeadmin.php. That's why everything appears twice.
It's also causing that error at the end of the lottery since the first lottery ends and deletes the info from the tables, the second instance of it can't end the lottery and produces that error we've been seeing.
SO, to fix the problem, open storeadmin.php and find both sets of lottery code and delete one of them. Mine works great now... clicking "Install".