Just for the records: I added the code like this:

$agent->show_progress(1);
$agent->add_handler("request_send",  sub { shift->dump; return });
$agent->add_handler("response_done", sub { shift->dump; return });
$agent->get("$1");
print $agent->content;
[download]

It gave me a bunch of feedback like:

(no content)
HTTP/1.1 301 Moved Permanently
Connection: close

So I found the redirects and could break down the problem. Thanks a lot again! Mc