Fatal Error with the Counter.php

[Tig]

Fatal error: Call to a member function Execute() on a non-object in /home/.ambale/whiskeyb/dicksgeneral.com/includes/counter.php on line 23

$date_now = date('Ymd');
$counter_query = "select startdate, counter, session_counter from " . TABLE_COUNTER_HISTORY . " where startdate='" . $date_now . "'";
LINE 23 ----> $counter = $db->Execute($counter_query); <---- LINE 23
if ($counter->RecordCount() <= 0) {
  $date_now = date('Ymd');
  $sql = "insert into " . TABLE_COUNTER_HISTORY . " (startdate, counter, session_counter) values ('" . $date_now . "', '1', '1')";
  $db->Execute($sql);
  $counter_startdate = $date_now;
  $counter_now = 1;
} else {
  $counter_startdate = $counter->fields['startdate'];
  $counter_now = ($counter->fields['counter'] + 1);
  $session_counter_now = ($counter->fields['session_counter'] + $session_counter);
  $sql = "update " . TABLE_COUNTER_HISTORY . " set counter = '" . $counter_now . "', session_counter ='" . $session_counter_now . "' where startdate='" . $date_now . "'";
  $db->Execute($sql);
}

How do I fix this error?

Much Thanks!