I'm not exactly sure what you're doing with these lines:

  $file =~ s/$dir\///g;
  $dir =~ s/\//\\/g;
[download]

If you could talk those through in English, I might be able to help.

However, if your intent is to get just the basename, be aware that $_ already has that. Simplifying your code, I'd just go with this:

find sub {
  return unless -f;
  my $size = -s;
  print
    "file: $_\n",
    "dir: $File::Find::dir\n",
    "size: $size\n";
}, $rootdir;
[download]

-- Randal L. Schwartz, Perl hacker