Aside from the minor problem of using $_ where you mean to use $next, there are two problems with

opendir(PWD,"$next") && my @files = readdir PWD
    or die "Open \"$_\" failed: $!";
[download]

First, you waste future readers' time. The few seconds you've saved by writing the above rather than

opendir(PWD,$name) or die "$name: $!";
my @files = readdir(PWD) or die "$name: $!";
[download]

Have just eclipsed by N x "what's this? uh.. oh, I see". Better, in my humble opinion, to write straightforward code. Sure, you have code "or die" twice, but in the scheme of things, that's a really minor nit.

Second, in the unikely event that opendir() succeeds and readdir() fails, you're presenting a misleading diagnostic.