Make sure your script is emailed to the submit address at that time. Every script that is in the mailbox at that time will still be reviewed for the contest.
If you script isn't finished yet at the 19th, but you still think the script is usable and good enough to make a chance... make sure you disable the half-done/buggy features that aren't ready yet in a way so users won't get trouble because of it and submit. After the contest you can send in an update for it, although we wont look at updates submitted after the end time to judge your script.
SendTo v1.9 has been submitted.
Screenshot Sender 4 has one bug and it was cause I used bitwise comparison so once I fix that version 4.1.0 should be submitted and released on the forums. I may release tonight or tomorrow on the forum.