1) in the populate list from array behavior you have set both the target and source list to use the child list.
the source list should be set to use the parent list, and the target list needs to be set to use the child list.
2) the code for the description on your page is:
$ATC_itemDescription = "".$row_rsUnisexChild['COLOR'] ."";// column binding
it needs to be changed to use the form post instead of the recordset data.