for the populate list from array behavior to be available, the following criteria must be met:
1) Create a Parent list
2) Create a child list
3) Create a recordset
4) Add the Create Dynamic List server behavior.
In Dreamweaver, there is a behaviors panel and a server behaviors panel.
If you are using a recordset to preselect a value for the parent list, you should also add the populate list from array behavior to set the chilld list to the onLoad event of the Body tag.