Yes, same happened here, but re-uploaded the two root directory .php files from the first zip and now works again.
Tried using the sound alert, but couldn't use the option for the user to trun it on and off, as it produced a security token issue, and the general alert appears to sound even when there are no messages.
PS. Alerts now working and online.php now shows the chat, no luck with photoplog, but not a major issue at this stage.