Same here, it errors store id empty
After checking system/config.php the id is there, some how it's not reading it.
Spoke with Dmitry, core guys will take a look, the ID is definently where it's supposed to be
// Unique AbanteCart store ID
define('UNIQUE_ID', '8cb315ce2ada09acfae3eae72a0a084d');
Some how, the upgrade is not reading it.