OK fixed that, updated and now 500 error. Im thinking this has to do with lines 32 to 38, check boxes don't seem to update so well, if you open the Insert Record behavior it has
<?php echo GetSQLValueString(isset($_POST['C1']) ? "true" : "", "defined","1","0"); ?>
as it's value, whereas everything else has
.($_POST['end_date']) .
I'm sure I could just use the lighting bolt to add it and it would fix it, but wanted you to see it for the EXT fix.