Did you try printing them? Can you post more of the code itself?
also adding
use CGI::Carp qw(fatalsToBrowser);
to the top of your program may prove useful.
update
And then in your code: die unless param('f');
Ted
-- "That which we persist in doing becomes easier, not that the task itself has become easier, but that our ability to perform it has improved."
--Ralph Waldo Emerson