You've got a problem with your assignment here:

           #####################
           # LINE 85 BELOW     #
           #####################
        $hitsdb{$page}{$key => {
                    'year' => $Year,
                    'month' => $Month,
                    'day' =>  $month_day,
                    'referer' => $referer,
                    'counter' => 1
                }};
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You're not setting $hitsdb{$page}{$key}, you're using $hitsdb{$page}{$key => ...} and doing nothing with it.

You probably meant to use:

        $hitsdb{$page}{$key} = {
                    'year' => $Year,
                    'month' => $Month,
                    'day' =>  $month_day,
                    'referer' => $referer,
                    'counter' => 1
                };
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