AbsoluteURI doesn't seem to work

Attempting to use absoluteURI on a Folder selectDlg or a File saveDlg and I can not get an absolute path - I always return this: ~/Desktop/tmp00000001
Which doesn't work. I'm using node.js and the fs system which won't accept the output of Extendscript.

Anyone have any good ideas? I'd post over on the Extension forum, but it's deader than a doornail.

function chooseExportFolder () {

    var myLocFolder = new File("~/Desktop").saveDlg("Enter a prefix for Export(s).");

    return myLocFolder.absoluteURI;

}