Problem:
the date field is not displayed correctly: instead of the
usual 'yyyy-mm-dd', it displays the int value e.g. '1232424123'

Fix:
in the file /class/xoopsform/formdatetime.php
locate-
$this->addElement(new XoopsFormTextDateSelect('', $name.'[date]', $size, $value));
and change it to-
$this->addElement(new XoopsFormTextDateSelect('', $name.'[date]', $size, date('Y-m-d', $value)));