Unable to work on pop up

[punit]

While recording through selenium, I am not able to save files.
There is save button on page when i click on that a new applet pop up
named "Save" opens where i need to type the address and press the Save
button, but selenium is not able to record in that pop up window.
I have tried select_window, select_popup but nothing works even
though i have tried through ruby get_all_window_names but its also
not able to detect the pop up.

Does Anybody know how to resolve this problem please reply.
Thanks in Advance