ListViewItem is not the Name of the object, it is the Class of the object I believe. I think the problem with your code is not that it's not going to work, I think it's that you're mapping to the wrong property.
Change your JScript code snippet to the following:
var ListView = Alias.long_long_object_Path.
var PropArray = new Array ("ClassName");
var ValuesArray = new Array ("ListViewItem");
var allShareUsers = ListView.FindChild(PropArray, ValuesArray, 1);
It could be that ClassName is replaced with WndClassName but I think this should work. Give it a try and let us know.
The other possibility is that this might not work either if the ListView items are dynamic... If they are owner-drawn, you might not be able to find them at all using the FindChild method.