Notes:
metro 6.22, powermac g4, powerbook g4
Open "Program Names" (keystroke ctrl+n), click "New..." or "Edit...", and try to edit the program names in the dialog.
Click "Open...", open an .ins file, click "Edit...", and try to edit the program names in the dialog.
Writing a .ins text file manually still imports ok, but you still can't edit it from the "Program Names" dialog.