I have confirmed this error is in JCOW and have asked for a fix many time. Even on JCOW/JCOWMASTER Birthday reminders disappear on the day of a users Birthday. I'm not sure if it is Timezone related. But Admin I'd love a real answer to the problem.</br >
FIX
</br >
dashboard.hook.php

Here is the correct code

function dashboard_friends_birthday() {
global $client;
$current = time() + $client['timezone']3600;
$m = gmdate('n',$current);
$d = gmdate('j',$current);
$next = $m+1;
if ($m<10) $m = '0'.$m;
if ($next > 12) $next = '01';
if ($d > 20) {
$nextm = " or (f.uid='{$client['id']}' and birthmonth='$next' and birthday<$d) ";
}
$res = sql_query("select u. from ".tb()."friends as f left join ".tb()."accounts as u on u.id=f.fid where (f.uid='{$client['id']}' and u.birthmonth='$m' and u.birthday>=$d) $nextm order by u.lastlogin desc limit 15");
$content = '<ul>';
while ($user = sql_fetch_array($res)) {
$total++;
if ($user['birthmonth'] < 10) $user['birthmonth'] = '0'.$user['birthmonth'];
if ($user['birthday'] < 10) $user['birthday'] = '0'.$user['birthday'];
$content .= '<li>'.url('u/'.$user['username'],$user['username']).' - <strong>'.$user['birthmonth'].'/'.$user['birthday'].'</strong></li>';
}
$content .= '</ul>';
if (!$total) $content = 'none';
return $content;
}