I don't see quite enough information to answer the question.

Could you replace your foreach loop with this and post the results?

foreach my $id (sort keys %hash)
{
    print "\$hash{$id} = '$hash{$id}'\n";
    my $counterValue = $hash{$id}{"counter"};
    print "    -> counter = '$counterValue'\n";
}
[download]

Thanks!