1) you have added the parent and child select lists outside of the add to cart form, the select lists need to be inside of the add to cart form
2) In the populate list from array behavior, you have not bound the source and target lists to the parant and child lists.
3) The code for the description filed isL
$ATC_itemDescription = "".$row_rsUnisexChild['COLOR'] ."";// column binding
you need to change this to use the form post instead of the recordset.