You might try the script below, where TextEdit is used as an example. Make sure that “Enable access for assistive devices” is checked under System Preferences > Universal Access.
Allow cascading windows to open as usual, and then run the script:
tell application "TextEdit" to activate -- replace TextEdit with your app
tell application "System Events"
tell process "TextEdit" -- replace with your app
try
set all_windows to every window
set the_position to value of attribute "AXPosition" of window 1
repeat with a_window in all_windows
set position of a_window to the_position
end repeat
end try
end tell
end tell
A version of the script was tested with apps TextEdit, Preview and Safari using Mac OS 10.4.11. Hope this helps.