Here is the fix which I have just tested. Within function childForm() in file include.session.inc change
if (is_array($value)) {
$offset = key($value);
} else {
$offset = 1;
} // if
to
if (is_array($value)) {
$offset = key($value);
} else {
$offset = 1;
if (count($object_array) > 1) {
// set to previous entry in array
$null = prev($object_array);
$objectname = key($object_array);
$dbobject = $object_array[$objectname];
} // if
} // if
Let me know if this works for you and I shall include it in the next release.