The official url for amfPHP is https://silexlabs.org/amfphp/ . The old domain(unlinked, they get enough as it is) has been hijacked for other purposes.
The domain had been registered by one of the early founders of the project, who has long since moved on. Despite our repeated requests he never passed over control of it to Silex Labs. And so the inevitable happened. It expired, and someone who is better at picking up domains the minute they expire snapped it up before we could. Sorry about that, but there is nothing we could do.