Use this piece of code
Code:
function probs_agenda_edit_accept($pid, $datum, $tijd, $klantid, $description, $addby) {
global $admin, $bgcolor2, $prefix, $db, $multilingual, $result;
include ("header.php");
GraphicAdmin();
title("Problems - Agenda - Edit - Save");
probs();
OpenTable();
$sql = "UPDATE ".$prefix."_probs_agenda SET datum='".date("Y-m-d", strtotime($datum))."', tijd='$tijd', klantid='$klantid', description='$description', addby='$addby' where id='$pid' LIMIT 1";
$db->sql_query($sql);
echo "Agenda item bijgewerkt";
echo "$sql";
CloseTable();
include("footer.php");
}