Well, 2 days ago our host did some upgrades on the server and changed some file permissions for security purposes.
So, there was some misconfiguration on our forum file permissions that prevented it from running.
Thanks to our perfect host support though (Renee) it was all fixed and got back to normal during my sleep time.
Just for the record I keep regular backups so even in case of disaster we would only lose a few days of conversations.
So, welcome back everyone!