Well, I got rid of it because I didn't want the SQL files lying around. There were no new ones in the archive so it didn't get recreated: There were no DB upgrades to be done. They're not PHP files, so it's not like they're critical to S9Y working - in fact, only the upgrader could possibly expect ...

This error occurs on upgrade if the sql directory doesn't exist:
PHP Warning: opendir(/path-to-s9y/sql/) [<a href='function.opendir'>function.opendir</a>]: failed to open dir: No such file or directory in /path-to-s9y/include/admin/upgrader.inc.php on line 155
Then this error occurs in an infinite ...