Well ... my suggestion is o put this little snip (progn (alert "I'm here") t) within the and structure --
(and
(progn (alert "I'm here") t)
(setq id (load_dcl "att.DCL"))
(start_list "atts")
(mapcar 'add_list lst)
(not (end_list))
(action_tile "cancel" "(done_dialog 0)")
...
)
And keep moving it ahead, line by line until it stops displaying the alert.