Hvorfor får jeg denne fejl på tæller

Hej

Jeg har et tællerscript på min indgangsside www.hgc.dk som pludeselig giver problemer.
Hvis I går ind på siden ser i fejlmeldingen i venstre rubrik "besøgende".

Følgende script giver problemet:

<div class="leftbox">
    <h4><img src="/graphics/markerw.gif" alt="" align="bottom">Besøgende</h4>
    <p>
      <?php
// Our log file;
$counter = "/counter.txt";

// Date logging;
$today = getdate();
$month = $today["month"];
$mday = $today["mday"];
$year = $today["year"];
$current_date = $mday . $month . $year;

// Log visit;
$fp = fopen($counter, "a");
$line = $_SERVER['REMOTE_ADDR'] . "|" . $mday . $month . $year . "\n";
$size = strlen($line);
fputs($fp, $line, $size);
fclose($fp);

// Read log file into array;
$contents = file($counter);

// Total hits;
$total_hits = sizeof($contents);

// Total hosts;
$total_hosts = array();
for ($i=0;$i<sizeof($contents);$i++) {
    $entry = explode("|", $contents[$i]);
    array_push($total_hosts, $entry[0]);
}
$total_hosts_size = sizeof(array_unique($total_hosts));

// Daily hits;
$daily_hits = array();
for ($i=0;$i<sizeof($contents);$i++) {
    $entry = explode("|", $contents[$i]);
    if ($current_date == chop($entry[1])) {
        array_push($daily_hits, $entry[0]);
    }
}
$daily_hits_size = sizeof($daily_hits);

// Daily hosts;
$daily_hosts = array();
for ($i=0;$i<sizeof($contents);$i++) {
    $entry = explode("|", $contents[$i]);
    if ($current_date == chop($entry[1])) {
        array_push($daily_hosts, $entry[0]);
    }
}
$daily_hosts_size = sizeof(array_unique($daily_hosts));

// Let's display everything;
echo "Totale hits: " . $total_hits . "<br>Totale brugere: " . $total_hosts_size . "<br>Daglige hits: " . $daily_hits_size . "<br>Daglige brugere: " . $daily_hosts_size;
?>
    </p>
  </div>