What part of perldoc perlsec am I missing?

I get this error: 

Insecure dependency in chdir while running 
with -T switch at ./simple line 21.

[download]
With this code: 
#!/usr/local/bin/perl -Tw
use strict;

my $sites_root='/home/sites';

delete @ENV{'IFS', 'CDPATH', 'ENV', 'BASH_ENV', 'PATH'};

opendir(DH,$sites_root) or die "1: $!\n";
my @sites=readdir(DH)or die "2: $!\n";
closedir(DH) or die "3: $!\n";
chdir($sites_root);

foreach  my $site (@sites){
        next if ($site eq '.') or ($site eq '..')
                or (not (-d "$sites_root/$site"));

        $site=~s/[^-\@\w\/]//;
        my $dir="$sites_root/$site";
        chdir($dir) or die "couldn't chdir to $dir : $!\n";

#tmp debug statment
system('/bin/pwd');
}

[download]
email: mandog

Edited 2002-01-02 by dvergin adding paren per user request

In reply to -T taint mode & chdir by mandog

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