Solution:
in /usr/local/lxlabs/kloxo/httpdocs/htmllib/phplib/lib/lxclass.php
find:
if ($ob->getClName() !== $this->getClName()) {
throw new lxException('objectclassname_doesnt_match', '');
}
and replace with:
if ($ob->getClName() !== $this->getClName()) {
// throw new lxException('objectclassname_doesnt_match', '');
}