From your description, maybe you want something like this:

#!/usr/bin/perl

use strict;
use warnings;
use File::Find;

my $base    = "/home/sthoenna/bleadperl/perl";

find(\&wanted, $base);

sub wanted {
   return unless ( -f "$File::Find::name" and $File::Find::name !~ m!/
+Encode/! )
;

   my $name  = "$File::Find::name";

   my $out   = join '.', grep defined, reverse( (split(m!/!, $name))[4
+..7] );
   print "$out\n";
}
[download]

Added warnings, reversing the names, removing unreached levels. Removed the extra my $out at the beginning; hope you realize that was a completely separate variable from the wanted sub's my $out. Removed the unused FileHandle stuff.

I like to always say m// for the first parameter to split to remind me that it is a regex...it's too easy to do something like split '+' and be surprised when it fails. (The exception is " " (a single blank) which split treats specially, not as a regex.)