In your case each input field has the same name. They are either called data_id or id. You need to create a input arrays
Try this
<input type="text" value="<?php echo $start_date; ?>" name="date_<?php echo $id; ?>[]">
<input type="hidden" value=<?php echo $id; ?> name="id[]">
On the package it said needs Windows 7 or better. So I installed Linux.