Will investigate further tomorrow, but issue arises here, in database.php lines 1297 to 1317
if (trim($_POST['expires'])=='')
{
$_POST['expires']=null;
}
else
{
$datetimeobj = new Date_Time_Converter($_POST['expires'] , "Y-m-d H:i:s");
$browsedatafield=$datetimeobj->convert($dateformatdetails['phpdate'].' H:i');
$_POST['expires']=$browsedatafield;
}

    if (trim($_POST['startdate'])=='')
    {
        $_POST['expires']=null;
    }
    else
    {
        $datetimeobj = new Date_Time_Converter($_POST['startdate'] , "Y-m-d H:i:s");
        $browsedatafield=$datetimeobj->convert($dateformatdetails['phpdate'].' H:i');                      
        $_POST['startdate']=$browsedatafield;
    }

which are converting perfectly nice dates into something completely wrong, and then attempting to insert a weird date/time format into mysql. As an example, my date which gets posted as 06.10.2009 then gets converted by these functions to 09.12.2005 01:00, and when that attempts to get inserted into the mysql date/time field it either causes an error(as discovered by Mazi) or MySql just makes it into 0000-00-00

The problem was twofold, with the lines
$datetimeobj = new Date_Time_Converter($_POST['expires'] , "Y-m-d H:i:s");
and
$browsedatafield=$datetimeobj->convert($dateformatdetails['phpdate'].' H:i');

Firstly, the date was being delivered in Y.m.d H:i:s format, not Y-m-d H:i:s. And then secondly, the date needed to be changed to a database friendly format for inserting, and $dateformatdetails['phpdate'] does not produce this. I copied the Date_Time_Converter->convert function from the update database function which worked, and that fixes the problem.