Basic Wordpress/PHP/Gravity Forms Coding

Hi, I need my Gravity Forms form submissions to be limited to a certain number of entries based on a datepicker field. So person number one selected 09.20.2014 and then persons number two and three come and select the same date, and then the form throws an error or the datepicker date becomes dark and cannot be clicked. I have the code, but it isn't working. I need help. I also need the form submission post to be scheduled for the date in that same field. I have this code but it also isn't working. I have attached the codes for you to review. If you can fix them, please do! Payment would be after successful work done and verify code. Thanks