You're using a hash reference called $where, but you've only defined a hash (i.e. not a reference) named %where.

Update: you probably want: 

     print $where{$_};

[download]
Update2: scratch that update. 
foreach (sort keys %count) {
      if ($count{$_} == 1) {
                print "user $_ is ONLY logged in at one place: ";
                print keys %{$where{$_}},"\n";  # print the single key
      } else {
                print "user $_ is logged in at: ";
                @where = sort keys %{$where{$_}};
                print "@where\n";
      }
}

[download]
Since $where{$user} always contains a hash ref.

"What should it profit a man, if he should win a flame war, yet lose his cool?"

In reply to Re: reference question by Joost
in thread reference question by convenientstore

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