This is a bug in MRBS. It has been fixed in the trunk since the 1.4.10 release. You can solve the problem in any of the following three ways:

(1) Downloading the latest version of MRBS from the trunk, or
(2) Setting the timezone using date.timezone in your php.ini file, or
(3) Patching your system by editing internalconfig.inc.php as follows:

Replace lines 74 and 75 which look like this:

  $start_first_slot = get_start_first_slot(1, 1, 2000);  // 1 Jan 2000 free of DST changes
  $start_last_slot  = get_start_last_slot(1, 1, 2000);

with the following:

  // Not safe to call get_start_first_slot() etc. here as the timezone won't necessarily have
  // been set yet(although quite often it will have been by php.ini using date.timezone)
  $start_first_slot = (($morningstarts * 60) + $morningstarts_minutes) * 60;
  $start_last_slot = (($eveningends * 60) + $eveningends_minutes) * 60;
  if ($start_last_slot < $start_first_slot)
  {
    $start_last_slot += 60*60*24;
  }

Campbell