You have a couple of errors.

You are running validate, which is supposed to output the $template, but you are not sending the proper html header until a couple of lines later.

Update: My bad. I see you are sending $c->header. However, you don't have to re-create your $cgi object. You can simply pass the object to the validate subroutine, and pick it up from there like so.

Next, $template->output() requires print before it to work.