To Specify folder use openDlg method not OpedDialog.
when using openDlg it is neccesary to first create a File object, set parent folder to desired folder for opening dialog and file name for default file name. then if OK is pressed the fsname will have file path
Without getting into a discussion about the new forums, it is cute to see a question unanswered and then in the "More like this" section you find the answer to the question. (didn't realize until after I posted)
By the way, you can also do
var myDefault = new Folder ("U:/xxx/zzz");
var myFiles = myDefault.openDlg(prompt string, filter string+pattern, multi-selection bollean);
Works in CS3. The Filename is left blank since we use a folder as a file... and the parent is the folder.