if ($fh == $lsn) { # this does not do what you think it does

##</code><code>##

$inbuffer{$fh} .= $buf; # Hash keys are stored as STRINGS.
...
foreach $client (keys %ready) { # So, when you are finally here
                                # $client is just a STRING
                                # It is no longer a reference
  handle($client); 
}